services: Cleanup class/struct fwd declarations

services/ui/public/cpp/window_compositor_frame_sink.h

 // Copyright 2014 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 SERVICES_UI_PUBLIC_CPP_WINDOW_COMPOSITOR_FRAME_SINK_H_
 #define SERVICES_UI_PUBLIC_CPP_WINDOW_COMPOSITOR_FRAME_SINK_H_
 
 #include "base/macros.h"
 #include "cc/ipc/mojo_compositor_frame_sink.mojom.h"
 #include "cc/output/compositor_frame_sink.h"
 #include "cc/output/context_provider.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/surface_id.h"
 #include "cc/surfaces/surface_id_allocator.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
-namespace gpu {
-class GpuChannelHost;
-}
-
 namespace ui {
 
 class WindowCompositorFrameSinkBinding;
 
 class WindowCompositorFrameSink
     : public cc::CompositorFrameSink,
       public cc::mojom::MojoCompositorFrameSinkClient,
       public cc::ExternalBeginFrameSourceClient {
  public:
   // static
@@ skipping 62 matching lines @@
           compositor_frame_sink_client);
 
   cc::mojom::MojoCompositorFrameSinkRequest compositor_frame_sink_request_;
   cc::mojom::MojoCompositorFrameSinkClientPtrInfo compositor_frame_sink_client_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowCompositorFrameSinkBinding);
 };
 }  // namespace ui
 
 #endif  // SERVICES_UI_PUBLIC_CPP_WINDOW_COMPOSITOR_FRAME_SINK_H_