[MPArch] Use IsOutermostMainFrame instead of checking the Parent

render_frame()->GetWebFrame()->Parent() is used to detect if the
primary main frame was navigated or a subframe. In MPArch, because
of nested frame trees, instead of checking Parent() we should
check IsOutermostMainFrame.

Bug: 1294378
Change-Id: I303569cec12c2bf6e00a6f8680c8379f142a0379
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3710067
Reviewed-by: Christoph Schwering <schwering@google.com>
Reviewed-by: Adithya Srinivasan <adithyas@chromium.org>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Liviu Tinta <liviutinta@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1016913}

components/autofill/content/renderer/form_tracker.cc

@@ -162,8 +162,8 @@ void FormTracker::DidStartNavigation(
     absl::optional<blink::WebNavigationType> navigation_type) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(form_tracker_sequence_checker_);
   blink::WebLocalFrame* navigated_frame = render_frame()->GetWebFrame();
-  // Ony handle main frame.
-  if (navigated_frame->Parent())
+  // Ony handle primary main frame.
+  if (!navigated_frame->IsOutermostMainFrame())
     return;
 
   // Bug fix for crbug.com/368690. isProcessingUserGesture() is false when

components/autofill/content/renderer/password_autofill_agent.cc

@@ -1380,7 +1380,9 @@ void PasswordAutofillAgent::OnFrameDetached() {
   // If a sub frame has been destroyed while the user was entering information
   // into a password form, try to save the data. See https://crbug.com/450806
   // for examples of sites that perform login using this technique.
-  if (render_frame()->GetWebFrame()->Parent() && browser_has_form_to_process_) {
+  // We are treating primary main frame and the root of embedded frames the same
+  // on purpose.
+  if (browser_has_form_to_process_ && render_frame()->GetWebFrame()->Parent()) {
     DCHECK(FrameCanAccessPasswordManager());
     GetPasswordManagerDriver().DynamicFormSubmission(
         SubmissionIndicatorEvent::FRAME_DETACHED);
@@ -1408,12 +1410,12 @@ void PasswordAutofillAgent::ReadyToCommitNavigation(
   }
 
   WebLocalFrame* navigated_frame = render_frame()->GetWebFrame();
-  if (navigated_frame->Parent()) {
-    LogMessage(logger.get(), Logger::STRING_FRAME_NOT_MAIN_FRAME);
-  } else {
+  if (navigated_frame->IsOutermostMainFrame()) {
     // This is a new navigation, so require a new user gesture before filling in
     // passwords.
     gatekeeper_.Reset();
+  } else {
+    LogMessage(logger.get(), Logger::STRING_FRAME_NOT_MAIN_FRAME);
   }
 
   CleanupOnDocumentShutdown();

components/autofill/content/renderer/password_generation_agent.cc

@@ -233,8 +233,8 @@ void PasswordGenerationAgent::BindPendingReceiver(
 
 void PasswordGenerationAgent::DidCommitProvisionalLoad(
     ui::PageTransition transition) {
-  // Update stats for main frame navigation.
-  if (!render_frame()->GetWebFrame()->Parent()) {
+  // Update stats for primary main frame navigation.
+  if (render_frame()->GetWebFrame()->IsOutermostMainFrame()) {
     if (current_generation_item_) {
       if (current_generation_item_->password_edited_) {
         password_generation::LogPasswordGenerationEvent(