GPU: Keep track of the last real context and real surface made current.

gpu/command_buffer/service/gl_context_virtual.cc

 // 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.
 
 #include "gpu/command_buffer/service/gl_context_virtual.h"
 
 #include "gpu/command_buffer/service/gl_state_restorer_impl.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 #include "ui/gl/gl_surface.h"
 
@@ skipping 90 matching lines @@
 }
 
 void GLContextVirtual::SetUnbindFboOnMakeCurrent() {
   shared_context_->SetUnbindFboOnMakeCurrent();
 }
 
 GLContextVirtual::~GLContextVirtual() {
   Destroy();
 }
 
+bool GLContextVirtual::IsVirtualContext() {
+  return true;
+}
+
 }  // namespace gpu