cc: Cleanup class/struct forward declarations

cc/output/software_output_device.h

 // 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.
 
 #ifndef CC_OUTPUT_SOFTWARE_OUTPUT_DEVICE_H_
 #define CC_OUTPUT_SOFTWARE_OUTPUT_DEVICE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/geometry/vector2d.h"
 
-class SkBitmap;
 class SkCanvas;
 
 namespace gfx {
 class VSyncProvider;
 }
 
 namespace cc {
 
 // This is a "tear-off" class providing software drawing support to
 // OutputSurface, such as to a platform-provided window framebuffer.
@@ skipping 34 matching lines @@
   sk_sp<SkSurface> surface_;
   std::unique_ptr<gfx::VSyncProvider> vsync_provider_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SoftwareOutputDevice);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_SOFTWARE_OUTPUT_DEVICE_H_