Revert of Make cc/paint have concrete types

third_party/WebKit/Source/platform/graphics/UnacceleratedImageBufferSurface.h

 /*
  * Copyright (c) 2013, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef UnacceleratedImageBufferSurface_h
 #define UnacceleratedImageBufferSurface_h
 
 #include "platform/graphics/ImageBufferSurface.h"
 #include "platform/graphics/paint/PaintCanvas.h"
+#include "platform/graphics/paint/PaintSurface.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT UnacceleratedImageBufferSurface
     : public ImageBufferSurface {
   WTF_MAKE_NONCOPYABLE(UnacceleratedImageBufferSurface);
   USING_FAST_MALLOC(UnacceleratedImageBufferSurface);
 
  public:
   UnacceleratedImageBufferSurface(
       const IntSize&,
       OpacityMode = NonOpaque,
       ImageInitializationMode = InitializeImagePixels,
       sk_sp<SkColorSpace> = nullptr,
       SkColorType = kN32_SkColorType);
   ~UnacceleratedImageBufferSurface() override;
 
   PaintCanvas* canvas() override;
   bool isValid() const override;
 
   sk_sp<SkImage> newImageSnapshot(AccelerationHint, SnapshotReason) override;
 
  private:
-  sk_sp<SkSurface> m_surface;
-  std::unique_ptr<PaintCanvas> m_canvas;
+  sk_sp<PaintSurface> m_surface;
 };
 
 }  // namespace blink
 
 #endif