MojoCompositorFrameSinkPrivate should support copy requests

cc/output/copy_output_result.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_OUTPUT_COPY_OUTPUT_RESULT_H_
 #define CC_OUTPUT_COPY_OUTPUT_RESULT_H_
 
 #include <memory>
 
 #include "base/memory/ptr_util.h"
@@ skipping 35 matching lines @@
 
   bool IsEmpty() const { return !HasBitmap() && !HasTexture(); }
   bool HasBitmap() const { return !!bitmap_ && !bitmap_->isNull(); }
   bool HasTexture() const { return texture_mailbox_.IsValid(); }
 
   gfx::Size size() const { return size_; }
   std::unique_ptr<SkBitmap> TakeBitmap();
   void TakeTexture(TextureMailbox* texture_mailbox,
                    std::unique_ptr<SingleReleaseCallback>* release_callback);
 
+  std::unique_ptr<SingleReleaseCallback> TakeReleaseCallback();
+
+  void set_release_callback(std::unique_ptr<SingleReleaseCallback> callback) {
+    release_callback_ = std::move(callback);
+  }
+
+  const gpu::Mailbox& mailbox() { return texture_mailbox_.mailbox(); }
+
  private:
   friend struct mojo::StructTraits<mojom::CopyOutputResultDataView,
                                    std::unique_ptr<CopyOutputResult>>;
 
   CopyOutputResult();
   explicit CopyOutputResult(std::unique_ptr<SkBitmap> bitmap);
   explicit CopyOutputResult(
       const gfx::Size& size,
       const TextureMailbox& texture_mailbox,
       std::unique_ptr<SingleReleaseCallback> release_callback);
 
   gfx::Size size_;
   std::unique_ptr<SkBitmap> bitmap_;
   TextureMailbox texture_mailbox_;
   std::unique_ptr<SingleReleaseCallback> release_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CopyOutputResult);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_COPY_OUTPUT_RESULT_H_