cc: Create ProxyBeginFrameSource

cc/test/begin_frame_args_test.h

Index: cc/test/begin_frame_args_test.h
diff --git a/cc/test/begin_frame_args_test.h b/cc/test/begin_frame_args_test.h
index 73aaf0219e0ed87c5309425015c050baa8ad5785..67933929afa3e6a517c683958bee1d72d1393668 100644
--- a/cc/test/begin_frame_args_test.h
+++ b/cc/test/begin_frame_args_test.h
@@ -46,11 +46,6 @@ BeginFrameArgs CreateExpiredBeginFrameArgsForTesting(
 // gtest helpers -- these *must* be in the same namespace as the types they
 // operate on.
 
-// Allow "EXPECT_EQ(args1, args2);"
-// We don't define operator!= because EXPECT_NE(args1, args2) isn't all that
-// sensible.
-bool operator==(const BeginFrameArgs& lhs, const BeginFrameArgs& rhs);
-
 // Allow gtest to pretty print begin frame args.
 ::std::ostream& operator<<(::std::ostream& os, const BeginFrameArgs& args);
 void PrintTo(const BeginFrameArgs& args, ::std::ostream* os);