cc: Dedup IPCs to return resources to client

cc/output/compositor_frame_ack.cc

Index: cc/output/compositor_frame_ack.cc
diff --git a/cc/output/compositor_frame_ack.cc b/cc/output/compositor_frame_ack.cc
deleted file mode 100644
index a411b42f5de5721204cf3e2d6b987bb7cd3029c1..0000000000000000000000000000000000000000
--- a/cc/output/compositor_frame_ack.cc
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "cc/output/compositor_frame_ack.h"
-
-namespace cc {
-
-CompositorFrameAck::CompositorFrameAck() {}
-
-CompositorFrameAck::~CompositorFrameAck() {}
-
-}  // namespace cc