Only show a beforeunload dialog if a frame has had a user gesture since its load.

content/public/test/browser_test_utils.h

Index: content/public/test/browser_test_utils.h
diff --git a/content/public/test/browser_test_utils.h b/content/public/test/browser_test_utils.h
index 1b063f643f397507953fef7c3f4f46bb0f9164c4..4122a90711a5abfdb751c244b17710fe53460231 100644
--- a/content/public/test/browser_test_utils.h
+++ b/content/public/test/browser_test_utils.h
@@ -101,6 +101,10 @@ void WaitForLoadStopWithoutSuccessCheck(WebContents* web_contents);
 // navigations should be refactored to do EXPECT_TRUE(WaitForLoadStop()).
 bool WaitForLoadStop(WebContents* web_contents);
 
+// If a test uses a beforeunload dialog, it must be prepared to avoid flakes.
+// This function collects everything that needs to be done.
+void PrepContentsForBeforeUnloadTest(WebContents* web_contents);
+
 #if defined(USE_AURA) || defined(OS_ANDROID)
 // If WebContent's view is currently being resized, this will wait for the ack
 // from the renderer that the resize is complete and for the