cc: Use the correct internal format for glCopyTexImage2D calls.

content/test/mailbox_output_surface.h

 // Copyright 2016 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_TEST_MAILBOX_OUTPUT_SURFACE_H_
 #define CONTENT_TEST_MAILBOX_OUTPUT_SURFACE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 26 matching lines @@
       scoped_refptr<cc::ContextProvider> worker_context_provider);
   ~MailboxOutputSurface() override;
 
   // cc::OutputSurface implementation.
   bool BindToClient(cc::OutputSurfaceClient* client) override;
   void DetachFromClient() override;
   void EnsureBackbuffer() override;
   void DiscardBackbuffer() override;
   void Reshape(const gfx::Size& size, float scale_factor, bool alpha) override;
   void BindFramebuffer() override;
+  uint32_t GetFramebufferCopyTextureFormat() override;
   void SwapBuffers(cc::CompositorFrame* frame) override;
 
  private:
   void ShortcutSwapAck(uint32_t output_surface_id,
                        std::unique_ptr<cc::GLFrameData> gl_frame_data);
   void OnSwapAck(uint32_t output_surface_id, const cc::CompositorFrameAck& ack);
 
   size_t GetNumAcksPending();
 
   struct TransferableFrame {
@@ skipping 17 matching lines @@
   uint32_t fbo_;
   bool is_backbuffer_discarded_;
 
   std::unique_ptr<cc::CompositorFrameAck> previous_frame_ack_;
   base::WeakPtrFactory<MailboxOutputSurface> weak_ptrs_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_TEST_MAILBOX_OUTPUT_SURFACE_H_