cc: Cleanup class/struct forward declarations

cc/test/fake_compositor_frame_sink_client.h

 // Copyright 2013 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.
 
 #ifndef CC_TEST_FAKE_COMPOSITOR_FRAME_SINK_CLIENT_H_
 #define CC_TEST_FAKE_COMPOSITOR_FRAME_SINK_CLIENT_H_
 
 #include "cc/output/compositor_frame_sink_client.h"
 #include "cc/output/managed_memory_policy.h"
 
 namespace cc {
 
-class CompositorFrameSink;
-
 class FakeCompositorFrameSinkClient : public CompositorFrameSinkClient {
  public:
   FakeCompositorFrameSinkClient() : memory_policy_(0) {}
 
   void SetBeginFrameSource(BeginFrameSource* source) override {}
   void DidReceiveCompositorFrameAck() override;
   void ReclaimResources(const ReturnedResourceArray& resources) override {}
   void DidLoseCompositorFrameSink() override;
   void SetExternalTilePriorityConstraints(
       const gfx::Rect& viewport_rect_for_tile_priority,
@@ skipping 14 matching lines @@
 
  private:
   int ack_count_ = 0;
   bool did_lose_compositor_frame_sink_called_ = false;
   ManagedMemoryPolicy memory_policy_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_COMPOSITOR_FRAME_SINK_CLIENT_H_