Use FrameIsAd to decide whether to isolate a frame in TopDocumentIsolation mode.

content/public/test/test_utils.h

Index: content/public/test/test_utils.h
diff --git a/content/public/test/test_utils.h b/content/public/test/test_utils.h
index f8afeece3a3c8c9318ca1bf6334c031b0f404ad5..66392df9cb5c1e3c8e20e40aac7a652d9efcd756 100644
--- a/content/public/test/test_utils.h
+++ b/content/public/test/test_utils.h
@@ -6,6 +6,7 @@
 #define CONTENT_PUBLIC_TEST_TEST_UTILS_H_
 
 #include <memory>
+#include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
@@ -84,6 +85,11 @@ bool AreAllSitesIsolatedForTesting();
 // the test; the flag will be read on the first real navigation.
 void IsolateAllSitesForTesting(base::CommandLine* command_line);
 
+// Enables a testing mode for TopDocumentIsolation by 1) enabling
+// features::kTopDocumentIsolation via |scoped_feature_list| and 2) forcing a
+// mode that isolates all cross-site frames.
+void EnableTopDocumentIsolationForTesting(base::CommandLine* command_line);
+
 // Resets the internal secure schemes/origins whitelist.
 void ResetSchemesAndOriginsWhitelist();
 
@@ -113,7 +119,7 @@ class MessageLoopRunner : public base::RefCountedThreadSafe<MessageLoopRunner> {
     DEFERRED,
   };
 
-  MessageLoopRunner(QuitMode mode = QuitMode::DEFERRED);
+  explicit MessageLoopRunner(QuitMode mode = QuitMode::DEFERRED);
 
   // Run the current MessageLoop unless the quit closure
   // has already been called.
@@ -275,7 +281,7 @@ class InProcessUtilityThreadHelper : public BrowserChildProcessObserver {
 // accessing it and causing use-after-free condition.
 class RenderFrameDeletedObserver : public WebContentsObserver {
  public:
-  RenderFrameDeletedObserver(RenderFrameHost* rfh);
+  explicit RenderFrameDeletedObserver(RenderFrameHost* rfh);
   ~RenderFrameDeletedObserver() override;
 
   // Overridden WebContentsObserver methods.