Remove duplicated code in AcceleratedSurface using PbufferGLContext instead....

app/gfx/gl/gl_context.h

 // Copyright (c) 2010 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 APP_GFX_GL_GL_CONTEXT_H_
 #define APP_GFX_GL_GL_CONTEXT_H_
 
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "gfx/native_widget_types.h"
@@ skipping 30 matching lines @@
   virtual void* GetHandle() = 0;
 
 #if !defined(OS_MACOSX)
   // Create a GL context that renders directly to a view.
   static GLContext* CreateViewGLContext(gfx::PluginWindowHandle window,
                                         bool multisampled);
 #endif
 
   // Create a GL context used for offscreen rendering. It is initially backed by
   // a 1x1 pbuffer. Use it to create an FBO to do useful rendering.
+  // |share_context|, if non-NULL, is a context which the internally created
+  // OpenGL context shares textures and other resources.
   static GLContext* CreateOffscreenGLContext(GLContext* shared_context);
 
  protected:
   bool InitializeCommon();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GLContext);
 };
 
 }  // namespace gfx
 
 #endif  // APP_GFX_GL_GL_CONTEXT_H_