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

ui/gl/gl_image.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_H_
 #define UI_GL_GL_IMAGE_H_
 
 #include "base/memory/ref_counted.h"
+#include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/overlay_transform.h"
 #include "ui/gl/gl_export.h"
 
 namespace gfx {
 
 // Encapsulates an image that can be bound to a texture, hiding platform
@@ skipping 10 matching lines @@
 
   // Get the internal format of the image.
   virtual unsigned GetInternalFormat() = 0;
 
   // Bind image to texture currently bound to |target|.
   virtual bool BindTexImage(unsigned target) = 0;
 
   // Release image from texture currently bound to |target|.
   virtual void ReleaseTexImage(unsigned target) = 0;
 
-  // Copy image to texture currently bound to |target|.
-  virtual bool CopyTexImage(unsigned target) = 0;
+  // Copy |rect| of image to |offset| in texture currently bound to |target|.
+  virtual bool CopyTexSubImage(unsigned target,
+                               const Point& offset,
+                               const Rect& rect) = 0;
 
   // Called before the texture is used for drawing.
   virtual void WillUseTexImage() = 0;
 
   // Called after the texture has been used for drawing.
   virtual void DidUseTexImage() = 0;
 
   // Called before the texture image data will be modified.
   virtual void WillModifyTexImage() = 0;
 
@@ skipping 12 matching lines @@
 
  private:
   friend class base::RefCounted<GLImage>;
 
   DISALLOW_COPY_AND_ASSIGN(GLImage);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_IMAGE_H_