content: Cleanup class/struct forward declarations

content/renderer/gpu/compositor_dependencies.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 CONTENT_RENDERER_GPU_COMPOSITOR_DEPENDENCIES_H_
 #define CONTENT_RENDERER_GPU_COMPOSITOR_DEPENDENCIES_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "cc/output/renderer_settings.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace cc {
-class BeginFrameSource;
-class ContextProvider;
 class ImageSerializationProcessor;
 class TaskGraphRunner;
 }
 
 namespace blink {
 namespace scheduler {
 class RendererScheduler;
 }
 }
 
@@ skipping 23 matching lines @@
   virtual cc::TaskGraphRunner* GetTaskGraphRunner() = 0;
   virtual bool AreImageDecodeTasksEnabled() = 0;
   virtual bool IsThreadedAnimationEnabled() = 0;
 
   virtual ~CompositorDependencies() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GPU_COMPOSITOR_DEPENDENCIES_H_