CodeHealth: Remove use of Value::GetAsInteger

This change removes the use of Value::GetAsInteger and replaces with
Value::is_int(), Value::GetInt(), Value::GetIfInt().

Bug: 1187004
Change-Id: I0cf57008424988019e3a2562bb28cab1469eb8cf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2831154
Commit-Queue: Minoru Chikamune <chikamune@chromium.org>
Reviewed-by: Dominic Battré <battre@chromium.org>
Cr-Commit-Position: refs/heads/master@{#873555}
diff --git a/components/prefs/json_pref_store_unittest.cc b/components/prefs/json_pref_store_unittest.cc
index 024f36a0..b2616c1 100644
--- a/components/prefs/json_pref_store_unittest.cc
+++ b/components/prefs/json_pref_store_unittest.cc
@@ -272,14 +272,13 @@
   EXPECT_FALSE(boolean);
 
   EXPECT_TRUE(pref_store->GetValue(kMaxTabs, &actual));
-  int integer = 0;
-  EXPECT_TRUE(actual->GetAsInteger(&integer));
-  EXPECT_EQ(20, integer);
+  ASSERT_TRUE(actual->is_int());
+  EXPECT_EQ(20, actual->GetInt());
   pref_store->SetValue(kMaxTabs, std::make_unique<Value>(10),
                        WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
   EXPECT_TRUE(pref_store->GetValue(kMaxTabs, &actual));
-  EXPECT_TRUE(actual->GetAsInteger(&integer));
-  EXPECT_EQ(10, integer);
+  ASSERT_TRUE(actual->is_int());
+  EXPECT_EQ(10, actual->GetInt());
 
   pref_store->SetValue(
       kLongIntPref,