aw: Do not assume functor will be called on UI thread

android_webview/browser/gl_view_renderer_manager.h

 // Copyright 2013 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 ANDROID_WEBVIEW_BROWSER_GL_VIEW_RENDERER_MANAGER_H_
 #define ANDROID_WEBVIEW_BROWSER_GL_VIEW_RENDERER_MANAGER_H_
 
 #include <list>
 
 #include "base/basictypes.h"
+#include "base/synchronization/lock.h"
+#include "base/threading/platform_thread.h"
 
 namespace android_webview {
 
 class BrowserViewRenderer;
 
 class GLViewRendererManager {
   typedef std::list<BrowserViewRenderer*> ListType;
  public:
   typedef ListType::iterator Key;
 
   GLViewRendererManager();
   ~GLViewRendererManager();
 
+  bool OnRenderThread() const;
+
   // If |key| is NullKey(), then |view| is inserted at the front and a new key
   // is returned. Otherwise |key| must point to |view| which is moved to the
   // front.
   Key DidDrawGL(Key key, BrowserViewRenderer* view);
 
   void NoLongerExpectsDrawGL(Key key);
 
   BrowserViewRenderer* GetMostRecentlyDrawn() const;
 
   Key NullKey();
 
  private:
+  void MarkRenderThread();
+
+  mutable base::Lock lock_;
+  base::PlatformThreadHandle render_thread_;
   ListType mru_list_;
 
   DISALLOW_COPY_AND_ASSIGN(GLViewRendererManager);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_GL_VIEW_RENDERER_MANAGER_H_