gpu: Add CHROMIUM_copy_image extension.

ui/gl/gl_image_stub.h

 // Copyright (c) 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 UI_GL_GL_IMAGE_STUB_H_
 #define UI_GL_GL_IMAGE_STUB_H_
 
 #include <stdint.h>
 
 #include "ui/gl/gl_export.h"
 #include "ui/gl/gl_image.h"
 
 namespace gl {
 
 // A GLImage that does nothing for unit tests.
 class GL_EXPORT GLImageStub : public GLImage {
  public:
   GLImageStub();
 
   // Overridden from GLImage:
   void Destroy(bool have_context) override {}
   gfx::Size GetSize() override;
   unsigned GetInternalFormat() override;
   bool BindTexImage(unsigned target, GLFence* fence) override;
   void ReleaseTexImage(unsigned target) override {}
   bool CopyTexImage(unsigned target) override;
   bool CopyTexSubImage(unsigned target,
                        const gfx::Point& offset,
                        const gfx::Rect& rect) override;
+  bool CopySubImageData(unsigned texture_id,
+                        const gfx::Point& offset,
+                        const gfx::Rect& rect,
+                        GLFence* in_fence,
+                        GLFence* out_fence) override;
   bool ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                             int z_order,
                             gfx::OverlayTransform transform,
                             const gfx::Rect& bounds_rect,
                             const gfx::RectF& crop_rect) override;
   void Flush() override {}
   void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
                     uint64_t process_tracing_id,
                     const std::string& dump_name) override {}
 
  protected:
   ~GLImageStub() override;
 };
 
 }  // namespace gl
 
 #endif  // UI_GL_GL_IMAGE_STUB_H_