cc: Cleanup class/struct forward declarations

cc/test/fake_scoped_ui_resource.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_SCOPED_UI_RESOURCE_H_
 #define CC_TEST_FAKE_SCOPED_UI_RESOURCE_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/resources/scoped_ui_resource.h"
 
 namespace cc {
 
-class LayerTreeHost;
-
 class FakeScopedUIResource : public ScopedUIResource {
  public:
   static std::unique_ptr<FakeScopedUIResource> Create(
       UIResourceManager* ui_resource_manager);
 
   UIResourceBitmap GetBitmap(UIResourceId uid, bool resource_lost) override;
   void DeleteResource();
   void ResetCounters();
 
   int resource_create_count;
   int lost_resource_count;
 
  private:
   explicit FakeScopedUIResource(UIResourceManager* ui_resource_manager);
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_SCOPED_UI_RESOURCE_H_