Test that main thread frames cease to fire during composited animation

content/browser/webkit_browsertest.cc

Index: content/browser/webkit_browsertest.cc
diff --git a/content/browser/webkit_browsertest.cc b/content/browser/webkit_browsertest.cc
index bd67587a327c33398fa3b89106235920a7783af7..0ed05b5005628655c8a4c1ecf1f56e435447bad4 100644
--- a/content/browser/webkit_browsertest.cc
+++ b/content/browser/webkit_browsertest.cc
@@ -4,6 +4,7 @@
 
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/test/browser_test_utils.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/shell/browser/shell.h"
@@ -75,4 +76,18 @@ IN_PROC_BROWSER_TEST_F(WebKitBrowserTest, PrerenderNoCrash) {
   EXPECT_FALSE(shell()->web_contents()->IsCrashed());
 }
 
+const char kTransformAnimationPage[] = "/transform-animation.html";
+IN_PROC_BROWSER_TEST_F(WebKitBrowserTest, TransformAnimationMainThreadFrames) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+  URLRequestAbortOnEndJob::AddUrlHandler();
+  GURL url = embedded_test_server()->GetURL(kTransformAnimationPage);
+
+  NavigateToURL(shell(), url);
+
+  WebContents* web_contents = shell()->web_contents();
+  FrameWatcher frame_watcher(web_contents);
+  frame_watcher.WaitFrames(3);
+  ASSERT_FALSE(frame_watcher.LastMetadata().is_main_thread_frame);
+}
+
 }  // namespace content