Clear up usage of Frame::IsAdRoot()

IsAdRoot() implies IsAdSubframe(). However, some callers check whether
IsAdRoot() || IsAdSubframe(). This cl removes these redundant checks and
adds documentation to the methods to clarify their meaning.

Change-Id: I62a437dead30141854351f3c9e7aecf9ecceec75
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2550429Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Alex Turner <alexmt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829675}

third_party/blink/renderer/core/frame/frame.h

@@ -210,8 +210,11 @@ class CORE_EXPORT Frame : public GarbageCollected<Frame> {
     return lifecycle_.GetState() == FrameLifecycle::kAttached;
   }
 
-  // Ad Tagging
+  // Whether the frame is considered to be an ad subframe by Ad Tagging. Returns
+  // true for both root and child ad subframes.
   bool IsAdSubframe() const;
+
+  // Whether the frame is considered to be a root ad subframe by Ad Tagging.
   bool IsAdRoot() const;
 
   // Called to make a frame inert or non-inert. A frame is inert when there

third_party/blink/renderer/core/loader/document_loader.cc

@@ -1431,9 +1431,9 @@ void DocumentLoader::DidCommitNavigation() {
   // Report legacy TLS versions after Page::DidCommitLoad, because the latter
   // clears the console.
   if (response_.IsLegacyTLSVersion()) {
-    GetFrameLoader().ReportLegacyTLSVersion(
-        response_.CurrentRequestUrl(), false /* is_subresource */,
-        frame_->IsAdSubframe() || frame_->IsAdRoot());
+    GetFrameLoader().ReportLegacyTLSVersion(response_.CurrentRequestUrl(),
+                                            false /* is_subresource */,
+                                            frame_->IsAdSubframe());
   }
 }
 

third_party/blink/renderer/modules/encryptedmedia/media_key_system_access.cc

@@ -152,8 +152,7 @@ void ReportMetrics(ExecutionContext* execution_context,
 
   ukm::builders::Media_EME_CreateMediaKeys builder(document->UkmSourceID());
   builder.SetKeySystem(KeySystemForUkm::kWidevine);
-  builder.SetIsAdFrame(
-      static_cast<int>(frame->IsAdRoot() || frame->IsAdSubframe()));
+  builder.SetIsAdFrame(static_cast<int>(frame->IsAdSubframe()));
   builder.SetIsCrossOrigin(static_cast<int>(frame->IsCrossOriginToMainFrame()));
   builder.SetIsTopFrame(static_cast<int>(frame->IsMainFrame()));
   builder.Record(document->UkmRecorder());

third_party/blink/renderer/modules/encryptedmedia/media_key_system_access_initializer_base.cc

@@ -219,8 +219,7 @@ void MediaKeySystemAccessInitializerBase::GenerateWarningAndReportMetrics()
   ukm::builders::Media_EME_RequestMediaKeySystemAccess builder(
       DomWindow()->UkmSourceID());
   builder.SetKeySystem(KeySystemForUkm::kWidevine);
-  builder.SetIsAdFrame(
-      static_cast<int>(frame->IsAdRoot() || frame->IsAdSubframe()));
+  builder.SetIsAdFrame(static_cast<int>(frame->IsAdSubframe()));
   builder.SetIsCrossOrigin(static_cast<int>(frame->IsCrossOriginToMainFrame()));
   builder.SetIsTopFrame(static_cast<int>(frame->IsMainFrame()));
   builder.SetVideoCapabilities(static_cast<int>(has_video_capabilities));