[mullet m3] Remove trigger source from AED::OnSuggestionsReturned.

In a recent change, the trigger source became source is part of the
suggestion query and is now passed to the AED in AED::OnQuery. The
trigger source passed to AED::OnSuggestionsReturned therefore  became
unused. This CL removes this unused parameter. As a result, the trigger
source is removed from the SingleFieldFormFiller interface and all its
implementations:
* AutocompleteHistoryManager
* IbanManager
* MerchantPromoCodeManager
* SingleFieldFormFillRounter

Existing tests are adjusted accordingly and 1 obsolete test is removed.

Bug: 1493361
Change-Id: If088e23ccd37cc8ef9c9a167aed85edaa8a10f30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5077270
Reviewed-by: Jan Keitel <jkeitel@google.com>
Commit-Queue: Timofey Chudakov <tchudakov@google.com>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1233246}
diff --git a/chrome/browser/autofill/autofill_autocomplete_browsertest.cc b/chrome/browser/autofill/autofill_autocomplete_browsertest.cc
index 2c91454..8051f6e 100644
--- a/chrome/browser/autofill/autofill_autocomplete_browsertest.cc
+++ b/chrome/browser/autofill/autofill_autocomplete_browsertest.cc
@@ -163,9 +163,8 @@
     base::MockCallback<SingleFieldFormFiller::OnSuggestionsReturnedCallback>
         callback;
     std::vector<Suggestion> suggestions;
-    EXPECT_CALL(callback, Run).WillOnce(testing::SaveArg<2>(&suggestions));
+    EXPECT_CALL(callback, Run).WillOnce(testing::SaveArg<1>(&suggestions));
     EXPECT_TRUE(autocomplete_history_manager()->OnGetSingleFieldSuggestions(
-        AutofillSuggestionTriggerSource::kFormControlElementClicked,
         test::CreateTestFormField(/*label=*/"", input_name, prefix,
                                   FormControlType::kInputText),
         manager().client(), callback.Get(), SuggestionsContext()));
diff --git a/chrome/browser/autofill/autofill_uitest_util.cc b/chrome/browser/autofill/autofill_uitest_util.cc
index baa60de..de4294b6 100644
--- a/chrome/browser/autofill/autofill_uitest_util.cc
+++ b/chrome/browser/autofill/autofill_uitest_util.cc
@@ -125,9 +125,7 @@
   std::vector<Suggestion> suggestions = {Suggestion(u"Test suggestion")};
   test_api(static_cast<BrowserAutofillManager&>(driver.GetAutofillManager()))
       .external_delegate()
-      ->OnSuggestionsReturned(
-          form.fields.front().global_id(), suggestions,
-          AutofillSuggestionTriggerSource::kFormControlElementClicked);
+      ->OnSuggestionsReturned(form.fields.front().global_id(), suggestions);
 }
 
 }  // namespace autofill
diff --git a/components/autofill/core/browser/autocomplete_history_manager.cc b/components/autofill/core/browser/autocomplete_history_manager.cc
index 0495cc4..5e1cc8f 100644
--- a/components/autofill/core/browser/autocomplete_history_manager.cc
+++ b/components/autofill/core/browser/autocomplete_history_manager.cc
@@ -77,7 +77,6 @@
 }
 
 bool AutocompleteHistoryManager::OnGetSingleFieldSuggestions(
-    AutofillSuggestionTriggerSource trigger_source,
     const FormFieldData& field,
     const AutofillClient& client,
     OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -90,9 +89,8 @@
   if (!IsMeaningfulFieldName(field.name) || !client.IsAutocompleteEnabled() ||
       field.form_control_type == FormControlType::kTextArea ||
       IsInAutofillSuggestionsDisabledExperiment()) {
-    SendSuggestions({},
-                    QueryHandler(field.global_id(), trigger_source, field.value,
-                                 std::move(on_suggestions_returned)));
+    SendSuggestions({}, QueryHandler(field.global_id(), field.value,
+                                     std::move(on_suggestions_returned)));
     return true;
   }
 
@@ -102,9 +100,8 @@
 
     // We can simply insert, since |query_handle| is always unique.
     pending_queries_.insert(
-        {query_handle,
-         QueryHandler(field.global_id(), trigger_source, field.value,
-                      std::move(on_suggestions_returned))});
+        {query_handle, QueryHandler(field.global_id(), field.value,
+                                    std::move(on_suggestions_returned))});
     return true;
   }
 
@@ -224,11 +221,9 @@
 
 AutocompleteHistoryManager::QueryHandler::QueryHandler(
     FieldGlobalId field_id,
-    AutofillSuggestionTriggerSource trigger_source,
     std::u16string prefix,
     OnSuggestionsReturnedCallback on_suggestions_returned)
     : field_id_(field_id),
-      trigger_source_(trigger_source),
       prefix_(std::move(prefix)),
       on_suggestions_returned_(std::move(on_suggestions_returned)) {}
 
@@ -256,7 +251,7 @@
   }
 
   std::move(query_handler.on_suggestions_returned_)
-      .Run(query_handler.field_id_, query_handler.trigger_source_, suggestions);
+      .Run(query_handler.field_id_, suggestions);
 }
 
 void AutocompleteHistoryManager::CancelAllPendingQueries() {
diff --git a/components/autofill/core/browser/autocomplete_history_manager.h b/components/autofill/core/browser/autocomplete_history_manager.h
index f5ef98e..5ccef697 100644
--- a/components/autofill/core/browser/autocomplete_history_manager.h
+++ b/components/autofill/core/browser/autocomplete_history_manager.h
@@ -44,7 +44,6 @@
 
   // SingleFieldFormFiller overrides:
   [[nodiscard]] bool OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource trigger_source,
       const FormFieldData& field,
       const AutofillClient& client,
       OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -81,7 +80,6 @@
   // with the appropriate response.
   struct QueryHandler {
     QueryHandler(FieldGlobalId field_id,
-                 AutofillSuggestionTriggerSource trigger_source,
                  std::u16string prefix,
                  OnSuggestionsReturnedCallback on_suggestions_returned);
     QueryHandler(const QueryHandler&) = delete;
@@ -91,12 +89,6 @@
     // The queried field ID.
     FieldGlobalId field_id_;
 
-    // Describes what caused the suggestions to trigger. This value was provided
-    // by the handler when requesting suggestions. It is temporarily stored
-    // while suggestions are queried, so it can be passed on to the
-    // `on_suggestions_returned_` callback.
-    AutofillSuggestionTriggerSource trigger_source_;
-
     // Prefix used to search suggestions, submitted by the handler.
     std::u16string prefix_;
 
diff --git a/components/autofill/core/browser/autocomplete_history_manager_unittest.cc b/components/autofill/core/browser/autocomplete_history_manager_unittest.cc
index f699ee6..8dc2935 100644
--- a/components/autofill/core/browser/autocomplete_history_manager_unittest.cc
+++ b/components/autofill/core/browser/autocomplete_history_manager_unittest.cc
@@ -445,8 +445,8 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 }
 
 // Make sure our handler is called at the right time.
@@ -467,14 +467,13 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response triggers a call to the handler's
   // OnSuggestionsReturned
   EXPECT_CALL(mock_callback,
               Run(test_field_.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::Truly(IsEmptySuggestionVector)));
 
   // Simulate response from DB.
@@ -498,16 +497,12 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response does not trigger a call to the
   // handler's OnSuggestionsReturned.
-  EXPECT_CALL(
-      mock_callback,
-      Run(test_field_.global_id(),
-          AutofillSuggestionTriggerSource::kFormControlElementClicked, _))
-      .Times(0);
+  EXPECT_CALL(mock_callback, Run(test_field_.global_id(), _)).Times(0);
 }
 
 // Tests that no suggestions are queried if the field name is filtered because
@@ -526,16 +521,12 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response does not trigger a call to the
   // handler's OnSuggestionsReturned.
-  EXPECT_CALL(
-      mock_callback,
-      Run(test_field_.global_id(),
-          AutofillSuggestionTriggerSource::kFormControlElementClicked, _))
-      .Times(0);
+  EXPECT_CALL(mock_callback, Run(test_field_.global_id(), _)).Times(0);
 }
 
 // Tests that the suggestions are queried if the field has meaningless substring
@@ -560,14 +551,11 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response triggers a call to the handler's
-  EXPECT_CALL(
-      mock_callback,
-      Run(test_field_.global_id(),
-          AutofillSuggestionTriggerSource::kFormControlElementClicked, _));
+  EXPECT_CALL(mock_callback, Run(test_field_.global_id(), _));
 
   autocomplete_manager_->OnWebDataServiceRequestDone(mocked_db_query_id,
                                                      std::move(mocked_results));
@@ -594,19 +582,17 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response triggers a call to the handler's
-  EXPECT_CALL(
-      mock_callback,
-      Run(test_field_.global_id(),
-          AutofillSuggestionTriggerSource::kFormControlElementClicked, _));
+  EXPECT_CALL(mock_callback, Run(test_field_.global_id(), _));
 
   autocomplete_manager_->OnWebDataServiceRequestDone(mocked_db_query_id,
                                                      std::move(mocked_results));
 }
 
+// Tests that we are correctly returning a suggestion back to the handler.
 TEST_F(AutocompleteHistoryManagerTest,
        SuggestionsReturned_InvokeHandler_SingleValue) {
   int mocked_db_query_id = 100;
@@ -625,50 +611,12 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response triggers a call to the handler's
   EXPECT_CALL(mock_callback,
               Run(test_field_.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
-                  UnorderedElementsAre(Field(
-                      &Suggestion::main_text,
-                      Suggestion::Text(expected_values[0].key().value(),
-                                       Suggestion::Text::IsPrimary(true))))));
-
-  // Simulate response from DB.
-  autocomplete_manager_->OnWebDataServiceRequestDone(mocked_db_query_id,
-                                                     std::move(mocked_results));
-}
-
-// Tests that we are correctly forwarding the value of the
-// `AutofillSuggestionTriggerSource` back to the handler.
-TEST_F(AutocompleteHistoryManagerTest,
-       SuggestionsReturned_InvokeHandler_PassesTriggerSource) {
-  int mocked_db_query_id = 100;
-
-  std::vector<AutocompleteEntry> expected_values = {
-      GetAutocompleteEntry(test_field_.name, u"SomePrefixOne")};
-
-  std::unique_ptr<WDTypedResult> mocked_results =
-      GetMockedDbResults(expected_values);
-
-  EXPECT_CALL(*web_data_service_,
-              GetFormValuesForElementName(test_field_.name, test_field_.value,
-                                          _, autocomplete_manager_.get()))
-      .WillOnce(Return(mocked_db_query_id));
-
-  // Simulate request for suggestions.
-  MockSuggestionsReturnedCallback mock_callback;
-  EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
-
-  // Setting up mock to verify that DB response triggers a call to the handler's
-  EXPECT_CALL(mock_callback,
-              Run(test_field_.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   UnorderedElementsAre(Field(
                       &Suggestion::main_text,
                       Suggestion::Text(expected_values[0].key().value(),
@@ -699,13 +647,12 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response triggers a call to the handler's
   EXPECT_CALL(mock_callback,
               Run(test_field_.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::Truly(IsEmptySuggestionVector)));
 
   // Simulate response from DB.
@@ -733,13 +680,12 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that DB response triggers a call to the handler's
   EXPECT_CALL(mock_callback,
               Run(test_field_.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   UnorderedElementsAre(Field(
                       &Suggestion::main_text,
                       Suggestion::Text(expected_values[0].key().value(),
@@ -782,8 +728,8 @@
 
   // Simulate request for suggestions.
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Simulate response from DB.
   autocomplete_manager_->OnWebDataServiceRequestDone(mocked_db_query_id,
@@ -826,21 +772,20 @@
   // Simulate request for the first suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Simulate request for the second suggestions (this will cancel the first
   // one).
   EXPECT_CALL(*web_data_service_, CancelRequest(mocked_db_query_id_first))
       .Times(1);
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Setting up mock to verify that we can get the second response first.
   EXPECT_CALL(mock_callback,
               Run(test_field_.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   UnorderedElementsAre(Field(
                       &Suggestion::main_text,
                       Suggestion::Text(expected_values_second[0].key().value(),
@@ -852,11 +797,7 @@
 
   // Setting up mock to verify that the handler doesn't get called for the first
   // request, which was cancelled.
-  EXPECT_CALL(
-      mock_callback,
-      Run(test_field_.global_id(),
-          AutofillSuggestionTriggerSource::kFormControlElementClicked, _))
-      .Times(0);
+  EXPECT_CALL(mock_callback, Run(test_field_.global_id(), _)).Times(0);
 
   // Simulate response from DB, first request comes back after.
   autocomplete_manager_->OnWebDataServiceRequestDone(
@@ -879,19 +820,15 @@
 
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      test_field_, autofill_client_, mock_callback.Get(),
+      SuggestionsContext()));
 
   // Simulate cancelling the request.
   EXPECT_CALL(*web_data_service_, CancelRequest(mocked_db_query_id));
   autocomplete_manager_->CancelPendingQueries();
 
   // Make sure the handler is not called when the DB responds.
-  EXPECT_CALL(
-      mock_callback,
-      Run(test_field_.global_id(),
-          AutofillSuggestionTriggerSource::kFormControlElementClicked, _))
-      .Times(0);
+  EXPECT_CALL(mock_callback, Run(test_field_.global_id(), _)).Times(0);
   autocomplete_manager_->OnWebDataServiceRequestDone(
       mocked_db_query_id, std::move(mocked_results_one));
 }
@@ -909,12 +846,10 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::Truly(IsEmptySuggestionVector)));
 
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, field,
-      autofill_client_, mock_callback.Get(), SuggestionsContext()));
+      field, autofill_client_, mock_callback.Get(), SuggestionsContext()));
 }
 
 TEST_F(AutocompleteHistoryManagerTest, DestructorCancelsRequests) {
@@ -927,8 +862,7 @@
 
   // Simulate request for suggestions.
   EXPECT_TRUE(autocomplete_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, base::DoNothing(), SuggestionsContext()));
+      test_field_, autofill_client_, base::DoNothing(), SuggestionsContext()));
 
   // Expect a cancel call.
   EXPECT_CALL(*web_data_service_, CancelRequest(mocked_db_query_id));
diff --git a/components/autofill/core/browser/autofill_external_delegate.cc b/components/autofill/core/browser/autofill_external_delegate.cc
index 3bb6712b..ac37d9c 100644
--- a/components/autofill/core/browser/autofill_external_delegate.cc
+++ b/components/autofill/core/browser/autofill_external_delegate.cc
@@ -235,9 +235,7 @@
 void AutofillExternalDelegate::OnSuggestionsReturned(
     FieldGlobalId field_id,
     const std::vector<Suggestion>& input_suggestions,
-    AutofillSuggestionTriggerSource trigger_source,
     bool is_all_server_suggestions) {
-  CHECK_EQ(trigger_source, trigger_source_);
   // Only include "Autofill Options" special menu item if we have Autofill
   // suggestions.
   bool has_autofill_suggestions = base::ranges::any_of(
diff --git a/components/autofill/core/browser/autofill_external_delegate.h b/components/autofill/core/browser/autofill_external_delegate.h
index 6bee759..5336acb4 100644
--- a/components/autofill/core/browser/autofill_external_delegate.h
+++ b/components/autofill/core/browser/autofill_external_delegate.h
@@ -94,11 +94,9 @@
 
   // Records query results and correctly formats them before sending them off
   // to be displayed. Called when an Autofill query result is available.
-  // TODO(crbug.com/1493361): `trigger_source` is unused, remove.
   virtual void OnSuggestionsReturned(
       FieldGlobalId field_id,
       const std::vector<Suggestion>& suggestions,
-      AutofillSuggestionTriggerSource trigger_source,
       bool is_all_server_suggestions = false);
 
   // Returns the last targeted field types to be filled. This does not
diff --git a/components/autofill/core/browser/autofill_external_delegate_unittest.cc b/components/autofill/core/browser/autofill_external_delegate_unittest.cc
index dc11e932..7c744b9 100644
--- a/components/autofill/core/browser/autofill_external_delegate_unittest.cc
+++ b/components/autofill/core/browser/autofill_external_delegate_unittest.cc
@@ -311,8 +311,7 @@
     std::vector<Suggestion> suggestions;
     suggestions.emplace_back();
     suggestions[0].popup_item_id = PopupItemId::kAddressEntry;
-    external_delegate().OnSuggestionsReturned(field_id, suggestions,
-                                              kDefaultTriggerSource);
+    external_delegate().OnSuggestionsReturned(field_id, suggestions);
   }
 
   Matcher<const FormData&> HasQueriedFormId() {
@@ -689,8 +688,8 @@
   std::vector<Suggestion> autofill_item = {
       Suggestion(PopupItemId::kAddressEntry)};
   autofill_item[0].payload = Suggestion::Guid(profile.guid());
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 
   EXPECT_CALL(manager(), FillOrPreviewProfileForm(
                              mojom::ActionPersistence::kFill,
@@ -729,8 +728,8 @@
               ShowAutofillPopup(PopupOpenArgsAre(kExpectedSuggestions), _));
   std::vector<Suggestion> autofill_item;
   autofill_item.emplace_back(/*main_text=*/u"", PopupItemId::kAddressEntry);
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 
   // Try calling OnSuggestionsReturned with no Autofill values and ensure
   // the datalist items are still shown.
@@ -740,8 +739,8 @@
           PopupOpenArgsAre(SuggestionVectorIdsAre(PopupItemId::kDatalistEntry)),
           _));
   autofill_item.clear();
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 }
 
 // Test that datalist values can get updated while a popup is showing.
@@ -774,8 +773,8 @@
   std::vector<Suggestion> autofill_item;
   autofill_item.emplace_back();
   autofill_item[0].popup_item_id = PopupItemId::kAddressEntry;
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 
   // This would normally get called from ShowAutofillPopup, but it is mocked so
   // we need to call OnPopupShown ourselves.
@@ -823,8 +822,8 @@
       Suggestion::Text(u"Rick", Suggestion::Text::IsPrimary(true));
   autofill_item[0].labels = {{Suggestion::Text(u"Deckard")}};
   autofill_item[0].popup_item_id = PopupItemId::kAddressEntry;
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 }
 
 // Test that we de-dupe autocomplete values against datalist values, keeping the
@@ -864,8 +863,7 @@
       Suggestion::Text(u"Cain", Suggestion::Text::IsPrimary(true));
   autocomplete_items[1].popup_item_id = PopupItemId::kAutocompleteEntry;
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            autocomplete_items,
-                                            kDefaultTriggerSource);
+                                            autocomplete_items);
 }
 
 // Test that the Autofill popup is able to display warnings explaining why
@@ -883,8 +881,8 @@
   autofill_item.emplace_back();
   autofill_item[0].popup_item_id =
       PopupItemId::kInsecureContextPaymentDisabledMessage;
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 
   EXPECT_THAT(open_args.suggestions,
               SuggestionVectorIdsAre(
@@ -913,7 +911,7 @@
       Suggestion::Text(u"Rick", Suggestion::Text::IsPrimary(true));
   suggestions[1].popup_item_id = PopupItemId::kAutocompleteEntry;
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            suggestions, kDefaultTriggerSource);
+                                            suggestions);
 }
 
 // Test that the Autofill delegate doesn't try and fill a form with a
@@ -954,7 +952,7 @@
   suggestions[0].labels = {{Suggestion::Text(u"My doctor's IBAN")}};
   suggestions[0].payload = Suggestion::ValueToFill(unmasked_iban_value);
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            suggestions, kDefaultTriggerSource);
+                                            suggestions);
 
   EXPECT_CALL(driver(), RendererShouldClearPreviewedForm());
   EXPECT_CALL(manager(),
@@ -992,7 +990,7 @@
   suggestions[0].main_text.value = promo_code_value;
   suggestions[0].labels = {{Suggestion::Text(u"12.34% off your purchase!")}};
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            suggestions, kDefaultTriggerSource);
+                                            suggestions);
 
   EXPECT_CALL(driver(), RendererShouldClearPreviewedForm());
   EXPECT_CALL(manager(),
@@ -1552,7 +1550,7 @@
   // This function tests the filling of existing plus addresses, which is why
   // `OfferPlusAddressCreation` need not be mocked.
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            suggestions, kDefaultTriggerSource);
+                                            suggestions);
 
   EXPECT_CALL(driver(), RendererShouldClearPreviewedForm());
   EXPECT_CALL(
@@ -1599,7 +1597,7 @@
   suggestions.emplace_back(/*main_text=*/u"",
                            PopupItemId::kCreateNewPlusAddress);
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            suggestions, kDefaultTriggerSource);
+                                            suggestions);
 
   EXPECT_CALL(driver(), RendererShouldClearPreviewedForm());
   external_delegate().DidSelectSuggestion(suggestions[0],
@@ -1650,7 +1648,7 @@
   std::vector<Suggestion> suggestions = {
       Suggestion(/*main_text=*/u"", PopupItemId::kCompose)};
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            suggestions, kDefaultTriggerSource);
+                                            suggestions);
 
   // Simulate accepting a Compose suggestion.
   AutofillComposeDelegate::ComposeCallback callback;
@@ -1826,8 +1824,7 @@
   EXPECT_CALL(client(), ShowAutofillPopup);
   EXPECT_CALL(client(), HideAutofillPopup(_)).Times(0);
 
-  external_delegate().OnSuggestionsReturned(field.global_id(), autofill_items,
-                                            kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(field.global_id(), autofill_items);
 }
 
 TEST_F(AutofillExternalDelegateUnitTest,
@@ -1952,8 +1949,7 @@
   std::vector<Suggestion> autofill_item;
   autofill_item.emplace_back(/*main_text=*/u"", PopupItemId::kAddressEntry);
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            autofill_item,
-                                            kDefaultTriggerSource, true);
+                                            autofill_item, true);
 }
 
 TEST_F(AutofillExternalDelegateUnitTest,
@@ -1971,8 +1967,7 @@
   std::vector<Suggestion> autofill_item;
   autofill_item.emplace_back(/*main_text=*/u"", PopupItemId::kAddressEntry);
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            autofill_item,
-                                            kDefaultTriggerSource, false);
+                                            autofill_item, false);
 }
 
 TEST_F(AutofillExternalDelegateUnitTest, ShouldUseNewSettingName) {
@@ -1990,8 +1985,8 @@
   std::vector<Suggestion> autofill_item;
   autofill_item.emplace_back(/*main_text=*/u"", PopupItemId::kAddressEntry);
   autofill_item[0].main_text.is_primary = Suggestion::Text::IsPrimary(true);
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 }
 
 // Test that browser autofill manager will handle the unmasking request for the
@@ -2030,8 +2025,7 @@
 
   external_delegate().OnSuggestionsReturned(
       queried_form_triggering_field_id_,
-      {Suggestion{PopupItemId::kAutocompleteEntry}},
-      AutofillSuggestionTriggerSource::kShowPromptAfterDialogClosed);
+      {Suggestion{PopupItemId::kAutocompleteEntry}});
 }
 
 // Tests that the prompt to show account cards shows up when the corresponding
@@ -2056,8 +2050,8 @@
   std::vector<Suggestion> autofill_item;
   autofill_item.emplace_back(/*main_text=*/u"", PopupItemId::kAddressEntry);
   autofill_item[0].main_text.is_primary = Suggestion::Text::IsPrimary(true);
-  external_delegate().OnSuggestionsReturned(
-      queried_form_triggering_field_id_, autofill_item, kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
+                                            autofill_item);
 }
 
 // Tests that the prompt to show account cards shows up when the corresponding
@@ -2074,8 +2068,7 @@
   EXPECT_CALL(client(),
               ShowAutofillPopup(PopupOpenArgsAre(kExpectedSuggestions), _));
   external_delegate().OnSuggestionsReturned(queried_form_triggering_field_id_,
-                                            std::vector<Suggestion>(),
-                                            kDefaultTriggerSource);
+                                            std::vector<Suggestion>());
 }
 
 #if BUILDFLAG(IS_IOS)
@@ -2087,8 +2080,8 @@
   client().set_last_queried_field(new_field_id);
   IssueOnQuery();
   EXPECT_CALL(client(), ShowAutofillPopup).Times(0);
-  external_delegate().OnSuggestionsReturned(
-      old_field_id, std::vector<Suggestion>(), kDefaultTriggerSource);
+  external_delegate().OnSuggestionsReturned(old_field_id,
+                                            std::vector<Suggestion>());
 }
 #endif
 
diff --git a/components/autofill/core/browser/autofill_test_utils.cc b/components/autofill/core/browser/autofill_test_utils.cc
index 0ac3ca0a..5a04b19 100644
--- a/components/autofill/core/browser/autofill_test_utils.cc
+++ b/components/autofill/core/browser/autofill_test_utils.cc
@@ -846,9 +846,8 @@
 
   std::vector<Suggestion> suggestions;
   suggestions.push_back(Suggestion(u"Test suggestion"));
-  autofill_external_delegate->OnSuggestionsReturned(
-      field.global_id(), suggestions,
-      AutofillSuggestionTriggerSource::kFormControlElementClicked);
+  autofill_external_delegate->OnSuggestionsReturned(field.global_id(),
+                                                    suggestions);
 }
 
 std::string ObfuscatedCardDigitsAsUTF8(const std::string& str,
diff --git a/components/autofill/core/browser/browser_autofill_manager.cc b/components/autofill/core/browser/browser_autofill_manager.cc
index 55a2ce4..497a72e6 100644
--- a/components/autofill/core/browser/browser_autofill_manager.cc
+++ b/components/autofill/core/browser/browser_autofill_manager.cc
@@ -716,7 +716,6 @@
   DCHECK(!cards.empty());
   external_delegate_->OnSuggestionsReturned(
       field_data.global_id(), cards,
-      AutofillSuggestionTriggerSource::kShowCardsFromAccount,
       should_display_gpay_logo);
 }
 
@@ -1138,7 +1137,7 @@
       case SuppressReason::kAblation:
         single_field_form_fill_router_->CancelPendingQueries();
         external_delegate_->OnSuggestionsReturned(field.global_id(),
-                                                  suggestions, trigger_source);
+                                                  suggestions);
         LOG_AF(log_manager())
             << LoggingScope::kFilling << LogMessage::kSuggestionSuppressed
             << " Reason: Ablation experiment";
@@ -1243,15 +1242,14 @@
       // TODO(crbug.com/1007974): The callback will only be called once.
       bool handled_by_single_field_form_filler =
           single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-              trigger_source, field, client(),
+              field, client(),
               base::BindRepeating(
                   [](base::WeakPtr<BrowserAutofillManager> self,
                      FieldGlobalId field_id,
-                     AutofillSuggestionTriggerSource trigger_source,
                      const std::vector<Suggestion>& suggestions) {
                     if (self) {
                       self->external_delegate_->OnSuggestionsReturned(
-                          field_id, suggestions, trigger_source);
+                          field_id, suggestions);
                     }
                   },
                   weak_ptr_factory_.GetWeakPtr()),
@@ -1289,7 +1287,6 @@
   if (show_suggestion) {
     // Send Autofill suggestions (could be an empty list).
     external_delegate_->OnSuggestionsReturned(field.global_id(), suggestions,
-                                              trigger_source,
                                               context.should_display_gpay_logo);
   }
 }
diff --git a/components/autofill/core/browser/browser_autofill_manager_unittest.cc b/components/autofill/core/browser/browser_autofill_manager_unittest.cc
index 51d108a..13ead1f 100644
--- a/components/autofill/core/browser/browser_autofill_manager_unittest.cc
+++ b/components/autofill/core/browser/browser_autofill_manager_unittest.cc
@@ -2220,13 +2220,11 @@
 
   // Mock returning some autocomplete `suggestions`.
   EXPECT_CALL(*single_field_form_fill_router(), OnGetSingleFieldSuggestions)
-      .WillOnce([&](AutofillSuggestionTriggerSource trigger_source,
-                    const FormFieldData& field, const AutofillClient& client,
+      .WillOnce([&](const FormFieldData& field, const AutofillClient& client,
                     SingleFieldFormFiller::OnSuggestionsReturnedCallback
                         on_suggestions_returned,
                     const SuggestionsContext& context) {
-        std::move(on_suggestions_returned)
-            .Run(field.global_id(), trigger_source, suggestions);
+        std::move(on_suggestions_returned).Run(field.global_id(), suggestions);
         return true;
       });
   GetAutofillSuggestions(
diff --git a/components/autofill/core/browser/iban_manager.cc b/components/autofill/core/browser/iban_manager.cc
index d5496c1..bb3740e 100644
--- a/components/autofill/core/browser/iban_manager.cc
+++ b/components/autofill/core/browser/iban_manager.cc
@@ -27,7 +27,6 @@
 IbanManager::~IbanManager() = default;
 
 bool IbanManager::OnGetSingleFieldSuggestions(
-    AutofillSuggestionTriggerSource trigger_source,
     const FormFieldData& field,
     const AutofillClient& client,
     OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -74,7 +73,7 @@
     return iban0->HasGreaterRankingThan(iban1, comparison_time);
   });
   SendIbanSuggestions(std::move(ibans), field,
-                      std::move(on_suggestions_returned), trigger_source);
+                      std::move(on_suggestions_returned));
 
   return true;
 }
@@ -118,8 +117,7 @@
 void IbanManager::SendIbanSuggestions(
     std::vector<const Iban*> ibans,
     const FormFieldData& field,
-    OnSuggestionsReturnedCallback on_suggestions_returned,
-    AutofillSuggestionTriggerSource trigger_source) {
+    OnSuggestionsReturnedCallback on_suggestions_returned) {
   // If the input box content equals any of the available IBANs, then
   // assume the IBAN has been filled, and don't show any suggestions.
   if (!field.value.empty() &&
@@ -134,7 +132,7 @@
   }
 
   std::move(on_suggestions_returned)
-      .Run(field.global_id(), trigger_source,
+      .Run(field.global_id(),
            AutofillSuggestionGenerator::GetSuggestionsForIbans(ibans));
 
   uma_recorder_.OnIbanSuggestionsShown(field.global_id());
diff --git a/components/autofill/core/browser/iban_manager.h b/components/autofill/core/browser/iban_manager.h
index d299634..414621c 100644
--- a/components/autofill/core/browser/iban_manager.h
+++ b/components/autofill/core/browser/iban_manager.h
@@ -39,7 +39,6 @@
 
   // SingleFieldFormFiller overrides:
   [[nodiscard]] bool OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource trigger_source,
       const FormFieldData& field,
       const AutofillClient& client,
       OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -77,8 +76,7 @@
   void SendIbanSuggestions(
       std::vector<const Iban*> ibans,
       const FormFieldData& field,
-      OnSuggestionsReturnedCallback on_suggestions_returned,
-      AutofillSuggestionTriggerSource trigger_source);
+      OnSuggestionsReturnedCallback on_suggestions_returned);
 
   // Filter out IBAN-based suggestions based on the following criteria:
   // For local IBANs: Filter out the IBAN value which does not starts with the
diff --git a/components/autofill/core/browser/iban_manager_unittest.cc b/components/autofill/core/browser/iban_manager_unittest.cc
index 1728a5f..dd206f31 100644
--- a/components/autofill/core/browser/iban_manager_unittest.cc
+++ b/components/autofill/core/browser/iban_manager_unittest.cc
@@ -165,7 +165,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(local_iban_suggestion_0),
                       MatchesTextAndPopupItemId(local_iban_suggestion_1),
@@ -178,8 +177,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 TEST_F(IbanManagerTest, PaymentsAutofillEnabledPrefOff_NoIbanSuggestionsShown) {
@@ -196,8 +194,7 @@
   // Because the "Save and autofill payment methods" toggle is off, the
   // suggestion handler should not be triggered.
   EXPECT_FALSE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 TEST_F(IbanManagerTest, IbanSuggestions_SeparatorAndFooter) {
@@ -215,7 +212,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(iban_suggestion_0),
                       MatchesTextAndPopupItemId(iban_suggestion_1),
@@ -225,8 +221,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 TEST_F(IbanManagerTest,
@@ -249,8 +244,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 TEST_F(IbanManagerTest,
@@ -273,7 +267,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(iban_suggestion_0),
                       MatchesTextAndPopupItemId(iban_suggestion_1),
@@ -284,8 +277,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 
   test_field.value = u"CH5604";
 
@@ -295,7 +287,6 @@
   // there are one separator and one footer suggestion displayed.
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(iban_suggestion_0),
                       MatchesTextAndPopupItemId(iban_suggestion_2),
@@ -305,8 +296,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 
   test_field.value = u"AB56";
 
@@ -318,8 +308,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 // Test that when the input text field is shorter than IBAN's prefix, all IBANs
@@ -348,7 +337,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(server_iban_suggestion_0),
                       MatchesTextAndPopupItemId(server_iban_suggestion_1),
@@ -359,8 +347,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 // Test that when the input text field is shorter than IBAN's prefix, only IBANs
@@ -389,7 +376,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(server_iban_suggestion_0),
                       MatchesTextAndPopupItemId(separator_suggestion),
@@ -399,8 +385,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 // Test that when there is no prefix present, all server IBANs should be
@@ -430,7 +415,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(server_iban_suggestion_0),
                       MatchesTextAndPopupItemId(server_iban_suggestion_1),
@@ -442,8 +426,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 
   test_field.value = u"AB567";
 
@@ -451,7 +434,6 @@
   // character is less than `kFieldLengthLimitOnServerIbanSuggestion`.
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::UnorderedElementsAre(
                       MatchesTextAndPopupItemId(server_iban_suggestion_0),
                       MatchesTextAndPopupItemId(server_iban_suggestion_1),
@@ -463,8 +445,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 // Test that when there is no prefix present, no server IBANs should be
@@ -500,8 +481,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 TEST_F(IbanManagerTest, DoesNotShowIbansForBlockedWebsite) {
@@ -520,8 +500,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 // Test that suggestions are returned on platforms that don't have an
@@ -541,7 +520,6 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(mock_callback,
               Run(test_field.global_id(),
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   testing::IsSupersetOf(
                       {MatchesTextAndPopupItemId(iban_suggestion_0)})));
 
@@ -549,8 +527,7 @@
   // Because all criteria are met to trigger returning to the handler,
   // the handler should be triggered and this should return true.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 TEST_F(IbanManagerTest, NotIbanFieldFocused_NoSuggestionsShown) {
@@ -569,8 +546,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 }
 
 // Tests that when showing IBAN suggestions is allowed by the site-specific
@@ -585,8 +561,7 @@
   // Simulate request for suggestions.
   // TODO: handle return value.
   std::ignore = iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, base::DoNothing(), context);
+      test_field, autofill_client_, base::DoNothing(), context);
 
   histogram_tester.ExpectUniqueSample(
       "Autofill.Iban.ShowSuggestionsBlocklistDecision",
@@ -612,8 +587,7 @@
   // Simulate request for suggestions.
   // TODO: handle return value.
   std::ignore = iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(),
+      test_field, autofill_client_, mock_callback.Get(),
       /*context=*/context);
 
   histogram_tester.ExpectUniqueSample(
@@ -634,8 +608,7 @@
   // Simulate request for suggestions.
   // TODO: handle return value.
   std::ignore = iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, base::DoNothing(),
+      test_field, autofill_client_, base::DoNothing(),
       /*context=*/context);
 
   histogram_tester.ExpectUniqueSample(
@@ -657,12 +630,10 @@
   // Simulate request for suggestions.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
 
   EXPECT_THAT(
       histogram_tester.GetAllSamples("Autofill.Iban.Suggestions"),
@@ -689,8 +660,7 @@
   // Simulate request for suggestions and select one suggested IBAN.
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
   iban_manager_.OnSingleFieldSuggestionSelected(u"", PopupItemId::kIbanEntry);
 
   histogram_tester.ExpectBucketCount(
@@ -701,8 +671,7 @@
       autofill_metrics::IbanSuggestionsEvent::kIbanSuggestionSelectedOnce, 1);
 
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
   iban_manager_.OnSingleFieldSuggestionSelected(u"", PopupItemId::kIbanEntry);
 
   histogram_tester.ExpectBucketCount(
@@ -729,8 +698,7 @@
   // The suggestion handler should be triggered as some IBANs are available.
   // However, no suggestions are returned due to the prefix match requirement.
   EXPECT_TRUE(iban_manager_.OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field,
-      autofill_client_, mock_callback.Get(), context));
+      test_field, autofill_client_, mock_callback.Get(), context));
   EXPECT_THAT(
       histogram_tester.GetAllSamples("Autofill.Iban.Suggestions"),
       BucketsAre(
diff --git a/components/autofill/core/browser/merchant_promo_code_manager.cc b/components/autofill/core/browser/merchant_promo_code_manager.cc
index 71b1404..64fe47f9 100644
--- a/components/autofill/core/browser/merchant_promo_code_manager.cc
+++ b/components/autofill/core/browser/merchant_promo_code_manager.cc
@@ -19,7 +19,6 @@
 MerchantPromoCodeManager::~MerchantPromoCodeManager() = default;
 
 bool MerchantPromoCodeManager::OnGetSingleFieldSuggestions(
-    AutofillSuggestionTriggerSource trigger_source,
     const FormFieldData& field,
     const AutofillClient& client,
     OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -39,8 +38,7 @@
             context.form_structure->main_frame_origin().GetURL());
     if (!promo_code_offers.empty()) {
       SendPromoCodeSuggestions(std::move(promo_code_offers), field,
-                               std::move(on_suggestions_returned),
-                               trigger_source);
+                               std::move(on_suggestions_returned));
       return true;
     }
   }
@@ -147,20 +145,18 @@
 void MerchantPromoCodeManager::SendPromoCodeSuggestions(
     std::vector<const AutofillOfferData*> promo_code_offers,
     const FormFieldData& field,
-    OnSuggestionsReturnedCallback on_suggestions_returned,
-    AutofillSuggestionTriggerSource trigger_source) {
+    OnSuggestionsReturnedCallback on_suggestions_returned) {
   // If the input box content equals any of the available promo codes, then
   // assume the promo code has been filled, and don't show any suggestions.
   for (const AutofillOfferData* promo_code_offer : promo_code_offers) {
     if (field.value == base::ASCIIToUTF16(promo_code_offer->GetPromoCode())) {
-      std::move(on_suggestions_returned)
-          .Run(field.global_id(), trigger_source, {});
+      std::move(on_suggestions_returned).Run(field.global_id(), {});
       return;
     }
   }
 
   std::move(on_suggestions_returned)
-      .Run(field.global_id(), trigger_source,
+      .Run(field.global_id(),
            AutofillSuggestionGenerator::
                GetPromoCodeSuggestionsFromPromoCodeOffers(promo_code_offers));
 
diff --git a/components/autofill/core/browser/merchant_promo_code_manager.h b/components/autofill/core/browser/merchant_promo_code_manager.h
index c5586a5..f367961 100644
--- a/components/autofill/core/browser/merchant_promo_code_manager.h
+++ b/components/autofill/core/browser/merchant_promo_code_manager.h
@@ -36,7 +36,6 @@
 
   // SingleFieldFormFiller overrides:
   [[nodiscard]] bool OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource trigger_source,
       const FormFieldData& field,
       const AutofillClient& client,
       OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -100,8 +99,7 @@
   void SendPromoCodeSuggestions(
       std::vector<const AutofillOfferData*> promo_code_offers,
       const FormFieldData& field,
-      OnSuggestionsReturnedCallback on_suggestions_returned,
-      AutofillSuggestionTriggerSource trigger_source);
+      OnSuggestionsReturnedCallback on_suggestions_returned);
 
   raw_ptr<PersonalDataManager> personal_data_manager_ = nullptr;
 
diff --git a/components/autofill/core/browser/merchant_promo_code_manager_unittest.cc b/components/autofill/core/browser/merchant_promo_code_manager_unittest.cc
index 3e26809..e6cba41 100644
--- a/components/autofill/core/browser/merchant_promo_code_manager_unittest.cc
+++ b/components/autofill/core/browser/merchant_promo_code_manager_unittest.cc
@@ -86,8 +86,6 @@
 
 TEST_F(MerchantPromoCodeManagerTest, ShowsPromoCodeSuggestions) {
   base::HistogramTester histogram_tester;
-  const auto trigger_source =
-      AutofillSuggestionTriggerSource::kFormControlElementClicked;
   std::string last_committed_origin_url = "https://www.example.com";
   FormData form_data;
   form_data.main_frame_origin =
@@ -107,11 +105,10 @@
   MockSuggestionsReturnedCallback mock_callback;
   EXPECT_CALL(
       mock_callback,
-      Run(_, trigger_source,
-          UnorderedElementsAre(
-              Field(&Suggestion::main_text, promo_code_suggestion.main_text),
-              Field(&Suggestion::popup_item_id, PopupItemId::kSeparator),
-              Field(&Suggestion::main_text, footer_suggestion.main_text))))
+      Run(_, UnorderedElementsAre(
+                 Field(&Suggestion::main_text, promo_code_suggestion.main_text),
+                 Field(&Suggestion::popup_item_id, PopupItemId::kSeparator),
+                 Field(&Suggestion::main_text, footer_suggestion.main_text))))
       .Times(3);
 
   // Simulate request for suggestions.
@@ -119,13 +116,13 @@
   // merchant site will be displayed instead of requesting Autocomplete
   // suggestions.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, test_field_, autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Trigger offers suggestions popup again to be able to test that we do not
   // log metrics twice for the same field.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, test_field_, autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Trigger offers suggestions popup again to be able to test that we log
@@ -134,7 +131,7 @@
       CreateTestFormField(/*label=*/"", "Some Other Name", "SomePrefix",
                           FormControlType::kInputTelephone);
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, other_field, autofill_client_, mock_callback.Get(),
+      other_field, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   histogram_tester.ExpectBucketCount(
@@ -165,8 +162,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/SuggestionsContext()));
 
   // Ensure that no metrics were logged.
@@ -210,8 +206,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Ensure that no metrics were logged.
@@ -253,8 +248,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Ensure that no metrics were logged.
@@ -296,8 +290,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Ensure that no metrics were logged.
@@ -343,8 +336,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Ensure that no metrics were logged.
@@ -390,8 +382,7 @@
 
   // Simulate request for suggestions.
   EXPECT_FALSE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // Ensure that no metrics were logged.
@@ -431,17 +422,16 @@
   // The field contains the promo code already, so check that we do not return
   // suggestions to the handler.
   MockSuggestionsReturnedCallback mock_callback;
-  EXPECT_CALL(mock_callback,
-              Run(_, _,
-                  testing::Truly(
-                      [](const std::vector<Suggestion>& returned_suggestions) {
-                        return returned_suggestions.empty();
-                      })));
+  EXPECT_CALL(
+      mock_callback,
+      Run(_, testing::Truly(
+                 [](const std::vector<Suggestion>& returned_suggestions) {
+                   return returned_suggestions.empty();
+                 })));
 
   // Simulate request for suggestions.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, mock_callback.Get(),
+      test_field_, autofill_client_, mock_callback.Get(),
       /*context=*/context));
 
   // No metrics should be logged because no suggestions were shown.
@@ -468,8 +458,6 @@
   // Set up the test.
   base::HistogramTester histogram_tester;
   std::u16string test_promo_code = u"test_promo_code";
-  const auto trigger_source =
-      AutofillSuggestionTriggerSource::kFormControlElementClicked;
   std::string last_committed_origin_url = "https://www.example.com";
   FormData form_data;
   form_data.main_frame_origin =
@@ -491,7 +479,7 @@
 
   // Simulate showing the promo code offers suggestions popup.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, test_field_, autofill_client_, base::DoNothing(),
+      test_field_, autofill_client_, base::DoNothing(),
       /*context=*/context));
 
   // Simulate selecting a promo code offer suggestion.
@@ -509,7 +497,7 @@
 
   // Simulate showing the promo code offers suggestions popup.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, test_field_, autofill_client_, base::DoNothing(),
+      test_field_, autofill_client_, base::DoNothing(),
       /*context=*/context));
 
   // Simulate selecting a promo code offer suggestion.
@@ -531,8 +519,6 @@
   // Set up the test.
   base::HistogramTester histogram_tester;
   std::u16string test_promo_code = u"test_promo_code";
-  const auto trigger_source =
-      AutofillSuggestionTriggerSource::kFormControlElementClicked;
   std::string last_committed_origin_url = "https://www.example.com";
   FormData form_data;
   form_data.main_frame_origin =
@@ -556,7 +542,7 @@
 
   // Simulate showing the promo code offers suggestions popup.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, test_field_, autofill_client_, base::DoNothing(),
+      test_field_, autofill_client_, base::DoNothing(),
       /*context=*/context));
 
   // Simulate selecting a promo code offer suggestion.
@@ -577,7 +563,7 @@
 
   // Simulate showing the promo code offers suggestions popup.
   EXPECT_TRUE(merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, test_field_, autofill_client_, base::DoNothing(),
+      test_field_, autofill_client_, base::DoNothing(),
       /*context=*/context));
 
   // Simulate selecting a promo code offer suggestion.
diff --git a/components/autofill/core/browser/mock_autocomplete_history_manager.h b/components/autofill/core/browser/mock_autocomplete_history_manager.h
index fa5d5b4..f743c04 100644
--- a/components/autofill/core/browser/mock_autocomplete_history_manager.h
+++ b/components/autofill/core/browser/mock_autocomplete_history_manager.h
@@ -18,8 +18,7 @@
 
   MOCK_METHOD(bool,
               OnGetSingleFieldSuggestions,
-              (AutofillSuggestionTriggerSource trigger_source,
-               const FormFieldData& field,
+              (const FormFieldData& field,
                const AutofillClient& client,
                SingleFieldFormFiller::OnSuggestionsReturnedCallback callback,
                const SuggestionsContext& context),
diff --git a/components/autofill/core/browser/mock_iban_manager.h b/components/autofill/core/browser/mock_iban_manager.h
index fd9d2ce..156e1e9 100644
--- a/components/autofill/core/browser/mock_iban_manager.h
+++ b/components/autofill/core/browser/mock_iban_manager.h
@@ -21,8 +21,7 @@
 
   MOCK_METHOD(bool,
               OnGetSingleFieldSuggestions,
-              (AutofillSuggestionTriggerSource trigger_source,
-               const FormFieldData& field,
+              (const FormFieldData& field,
                const AutofillClient& client,
                SingleFieldFormFiller::OnSuggestionsReturnedCallback callback,
                const SuggestionsContext& context),
diff --git a/components/autofill/core/browser/mock_merchant_promo_code_manager.h b/components/autofill/core/browser/mock_merchant_promo_code_manager.h
index 8954490..51dd8554 100644
--- a/components/autofill/core/browser/mock_merchant_promo_code_manager.h
+++ b/components/autofill/core/browser/mock_merchant_promo_code_manager.h
@@ -18,8 +18,7 @@
 
   MOCK_METHOD(bool,
               OnGetSingleFieldSuggestions,
-              (AutofillSuggestionTriggerSource trigger_source,
-               const FormFieldData& field,
+              (const FormFieldData& field,
                const AutofillClient& client,
                SingleFieldFormFiller::OnSuggestionsReturnedCallback callback,
                const SuggestionsContext& context),
diff --git a/components/autofill/core/browser/mock_single_field_form_fill_router.h b/components/autofill/core/browser/mock_single_field_form_fill_router.h
index 8aa6cd1..cbf95b35 100644
--- a/components/autofill/core/browser/mock_single_field_form_fill_router.h
+++ b/components/autofill/core/browser/mock_single_field_form_fill_router.h
@@ -29,8 +29,7 @@
               (override));
   MOCK_METHOD(bool,
               OnGetSingleFieldSuggestions,
-              (AutofillSuggestionTriggerSource trigger_source,
-               const FormFieldData& field,
+              (const FormFieldData& field,
                const AutofillClient& client,
                SingleFieldFormFiller::OnSuggestionsReturnedCallback callback,
                const SuggestionsContext& context),
diff --git a/components/autofill/core/browser/single_field_form_fill_router.cc b/components/autofill/core/browser/single_field_form_fill_router.cc
index 29ebea5..f0f7bc3 100644
--- a/components/autofill/core/browser/single_field_form_fill_router.cc
+++ b/components/autofill/core/browser/single_field_form_fill_router.cc
@@ -62,7 +62,6 @@
 }
 
 bool SingleFieldFormFillRouter::OnGetSingleFieldSuggestions(
-    AutofillSuggestionTriggerSource trigger_source,
     const FormFieldData& field,
     const AutofillClient& client,
     OnSuggestionsReturnedCallback on_suggestions_returned,
@@ -70,17 +69,15 @@
   // Retrieving suggestions for a new field; select the appropriate filler.
   if (merchant_promo_code_manager_ &&
       merchant_promo_code_manager_->OnGetSingleFieldSuggestions(
-          trigger_source, field, client, on_suggestions_returned, context)) {
+          field, client, on_suggestions_returned, context)) {
     return true;
   }
-  if (iban_manager_ &&
-      iban_manager_->OnGetSingleFieldSuggestions(
-          trigger_source, field, client, on_suggestions_returned, context)) {
+  if (iban_manager_ && iban_manager_->OnGetSingleFieldSuggestions(
+                           field, client, on_suggestions_returned, context)) {
     return true;
   }
   return autocomplete_history_manager_->OnGetSingleFieldSuggestions(
-      trigger_source, field, client, std::move(on_suggestions_returned),
-      context);
+      field, client, std::move(on_suggestions_returned), context);
 }
 
 void SingleFieldFormFillRouter::OnWillSubmitFormWithFields(
diff --git a/components/autofill/core/browser/single_field_form_fill_router.h b/components/autofill/core/browser/single_field_form_fill_router.h
index 0421d06..3517a449 100644
--- a/components/autofill/core/browser/single_field_form_fill_router.h
+++ b/components/autofill/core/browser/single_field_form_fill_router.h
@@ -46,7 +46,6 @@
 
   // SingleFieldFormFiller overrides:
   [[nodiscard]] bool OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource trigger_source,
       const FormFieldData& field,
       const AutofillClient& client,
       OnSuggestionsReturnedCallback on_suggestions_returned,
diff --git a/components/autofill/core/browser/single_field_form_fill_router_unittest.cc b/components/autofill/core/browser/single_field_form_fill_router_unittest.cc
index 73e904bb..2ccb196 100644
--- a/components/autofill/core/browser/single_field_form_fill_router_unittest.cc
+++ b/components/autofill/core/browser/single_field_form_fill_router_unittest.cc
@@ -101,7 +101,6 @@
 
     EXPECT_EQ(test_field_.should_autocomplete,
               single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-                  AutofillSuggestionTriggerSource::kFormControlElementClicked,
                   test_field_, autofill_client_, base::DoNothing(),
                   /*context=*/SuggestionsContext()));
   }
@@ -224,7 +223,6 @@
         .WillOnce(testing::Return(true));
 
     EXPECT_TRUE(single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-        AutofillSuggestionTriggerSource::kFormControlElementClicked,
         test_field_, autofill_client_, base::DoNothing(),
         SuggestionsContext()));
   }
@@ -247,8 +245,7 @@
   // autocomplete. SingleFieldFormFillRouter::OnGetSingleFieldSuggestions()
   // should return true.
   EXPECT_TRUE(single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, base::DoNothing(), SuggestionsContext()));
+      test_field_, autofill_client_, base::DoNothing(), SuggestionsContext()));
 }
 
 // Ensure that the router routes to AutocompleteHistoryManager for this
@@ -272,8 +269,7 @@
   // autocomplete. SingleFieldFormFillRouter::OnGetSingleFieldSuggestions()
   // should return true.
   EXPECT_TRUE(single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, base::DoNothing(), SuggestionsContext()));
+      test_field_, autofill_client_, base::DoNothing(), SuggestionsContext()));
 }
 
 // Ensure that the router routes to MerchantPromoCodeManager for this
@@ -314,8 +310,7 @@
   // All SingleFieldFormFillers returned false, so we should return false as we
   // did not attempt to display any single field form fill suggestions.
   EXPECT_FALSE(single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, base::DoNothing(), SuggestionsContext()));
+      test_field_, autofill_client_, base::DoNothing(), SuggestionsContext()));
 }
 
 // Ensure that the router routes to AutocompleteHistoryManager for this
@@ -335,8 +330,7 @@
   // autocomplete. SingleFieldFormFillRouter::OnGetSingleFieldSuggestions()
   // should return true.
   EXPECT_TRUE(single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, base::DoNothing(), SuggestionsContext()));
+      test_field_, autofill_client_, base::DoNothing(), SuggestionsContext()));
 }
 
 // Ensure that the router routes to AutocompleteHistoryManager for this
@@ -360,8 +354,7 @@
   // autocomplete. SingleFieldFormFillRouter::OnGetSingleFieldSuggestions()
   // should return true.
   EXPECT_TRUE(single_field_form_fill_router_->OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource::kFormControlElementClicked, test_field_,
-      autofill_client_, base::DoNothing(), SuggestionsContext()));
+      test_field_, autofill_client_, base::DoNothing(), SuggestionsContext()));
 }
 
 // Ensure that the router routes to IbanManager for this
diff --git a/components/autofill/core/browser/single_field_form_filler.h b/components/autofill/core/browser/single_field_form_filler.h
index b84cd4ad..e90ae73f 100644
--- a/components/autofill/core/browser/single_field_form_filler.h
+++ b/components/autofill/core/browser/single_field_form_filler.h
@@ -31,7 +31,6 @@
   // only one of them will end up calling it).
   using OnSuggestionsReturnedCallback =
       base::RepeatingCallback<void(FieldGlobalId,
-                                   AutofillSuggestionTriggerSource,
                                    const std::vector<Suggestion>&)>;
 
   SingleFieldFormFiller();
@@ -56,7 +55,6 @@
   // SingleFieldFormFillers to offer filling the field. The callback can happen
   // synchronously even before OnGetSingleFieldSuggestions returns true.
   [[nodiscard]] virtual bool OnGetSingleFieldSuggestions(
-      AutofillSuggestionTriggerSource trigger_source,
       const FormFieldData& field,
       const AutofillClient& client,
       OnSuggestionsReturnedCallback on_suggestions_returned,
diff --git a/components/autofill/core/browser/test_autofill_external_delegate.cc b/components/autofill/core/browser/test_autofill_external_delegate.cc
index b17de0f9..b8349b59 100644
--- a/components/autofill/core/browser/test_autofill_external_delegate.cc
+++ b/components/autofill/core/browser/test_autofill_external_delegate.cc
@@ -49,7 +49,6 @@
 void TestAutofillExternalDelegate::OnSuggestionsReturned(
     FieldGlobalId field_id,
     const std::vector<Suggestion>& suggestions,
-    AutofillSuggestionTriggerSource trigger_source,
     bool is_all_server_suggestions) {
   on_suggestions_returned_seen_ = true;
   field_id_ = field_id;
@@ -59,8 +58,8 @@
   // If necessary, call the superclass's OnSuggestionsReturned in order to
   // execute logic relating to showing the popup or not.
   if (call_parent_methods_)
-    AutofillExternalDelegate::OnSuggestionsReturned(
-        field_id, suggestions, trigger_source_, is_all_server_suggestions);
+    AutofillExternalDelegate::OnSuggestionsReturned(field_id, suggestions,
+                                                    is_all_server_suggestions);
 }
 
 bool TestAutofillExternalDelegate::HasActiveScreenReader() const {
diff --git a/components/autofill/core/browser/test_autofill_external_delegate.h b/components/autofill/core/browser/test_autofill_external_delegate.h
index 6b25fe44..589c02ca 100644
--- a/components/autofill/core/browser/test_autofill_external_delegate.h
+++ b/components/autofill/core/browser/test_autofill_external_delegate.h
@@ -33,7 +33,6 @@
                AutofillSuggestionTriggerSource trigger_source) override;
   void OnSuggestionsReturned(FieldGlobalId field_id,
                              const std::vector<Suggestion>& suggestions,
-                             AutofillSuggestionTriggerSource trigger_source,
                              bool is_all_server_suggestions) override;
   bool HasActiveScreenReader() const override;
   void OnAutofillAvailabilityEvent(