AnonymousIframe: Reenable wpt about initial empty document.

The test was flaky. I still don't know why. This patch enables it back,
with a description of the assertion, so that we can find which one is
failing.

Bug: 1356118
Change-Id: I9eb0aa24f743eee41622d18310270457f03d19c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4055712
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Paul Semel <paulsemel@chromium.org>
Auto-Submit: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1076104}
diff --git a/third_party/blink/web_tests/TestExpectations b/third_party/blink/web_tests/TestExpectations
index d0f03c2..9beb405bb 100644
--- a/third_party/blink/web_tests/TestExpectations
+++ b/third_party/blink/web_tests/TestExpectations
@@ -7450,11 +7450,6 @@
 crbug.com/1356118 [ Mac ] virtual/async-script-scheduling-finished-parsing/wpt_internal/async-script-scheduling/execution-order.sub.html [ Failure Pass ]
 crbug.com/1356118 [ Linux ] virtual/async-script-scheduling-finished-parsing/wpt_internal/async-script-scheduling/execution-order.sub.html [ Failure Pass ]
 
-# Sheriff 2022-08-26
-crbug.com/1356118 [ Linux ] external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.html [ Failure Pass ]
-crbug.com/1356118 [ Linux ] virtual/fenced-frame-mparch/external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.html [ Failure Pass ]
-crbug.com/1356118 [ Linux ] virtual/partitioned-cookies/external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.html [ Failure Pass ]
-
 # Sheriff 2022-08-30
 
 # TODO(crbug.com/1358147): Re-enable this test
diff --git a/third_party/blink/web_tests/external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.js b/third_party/blink/web_tests/external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.js
index fc58aae..37678ff 100644
--- a/third_party/blink/web_tests/external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.js
+++ b/third_party/blink/web_tests/external/wpt/html/anonymous-iframe/local-storage-initial-empty-document.tentative.https.window.js
@@ -60,11 +60,15 @@
     send("${queue_C}", value_E);
   `);
 
-  // Verify the credentialless iframe and the normal one do not have access to each
-  // other.
-  assert_equals(await receive(queue_B), value_D); // key_D
-  assert_equals(await receive(queue_B), "");      // key_E
-  assert_equals(await receive(queue_C), "");      // key_D
-  assert_equals(await receive(queue_C), value_E); // key_E
-}, "Local storage is correctly partitioned with regards to credentialless iframe " +
-   "in initial empty documents.");
+  // Verify the credentialless iframe and the normal one do not have access to
+  // each other.
+  assert_equals(await receive(queue_B), value_D, // key_D
+    "Credentialless iframe can access credentialless context");
+  assert_equals(await receive(queue_B), "",      // key_E
+    "Credentialless iframe can't access credentialled context");
+  assert_equals(await receive(queue_C), "",      // key_D
+    "Credentialled iframe can't access credentialless context");
+  assert_equals(await receive(queue_C), value_E, // key_E
+    "Credentialled iframe can access credentialled context");
+}, "Local storage is correctly partitioned with regards to credentialless " +
+   "iframe in initial empty documents.");