ui: Add sub region copy support to GLImage::CopyTexImage.

ui/gl/gl_image_memory.h

 // Copyright 2014 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_MEMORY_H_
 #define UI_GL_GL_IMAGE_MEMORY_H_
 
 #include "ui/gl/gl_image.h"
 
 #if defined(OS_WIN) || defined(USE_X11) || defined(OS_ANDROID) || \
@@ skipping 17 matching lines @@
 
   bool Initialize(const unsigned char* memory,
                   GpuMemoryBuffer::Format format);
 
   // Overridden from GLImage:
   void Destroy(bool have_context) override;
   Size GetSize() override;
   unsigned GetInternalFormat() override;
   bool BindTexImage(unsigned target) override;
   void ReleaseTexImage(unsigned target) override {}
-  bool CopyTexImage(unsigned target) override;
+  bool CopyTexSubImage(unsigned target,
+                       const Point& offset,
+                       const Rect& rect) override;
   void WillUseTexImage() override;
   void DidUseTexImage() override;
   void WillModifyTexImage() override {}
   void DidModifyTexImage() override {}
   bool ScheduleOverlayPlane(AcceleratedWidget widget,
                             int z_order,
                             OverlayTransform transform,
                             const Rect& bounds_rect,
                             const RectF& crop_rect) override;
 
@@ skipping 15 matching lines @@
   unsigned egl_texture_id_;
   EGLImageKHR egl_image_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(GLImageMemory);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_IMAGE_MEMORY_H_