Implement the Platform::sharedOffscreenGraphicsContext3D method.

webkit/support/test_webkit_platform_support.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 WEBKIT_SUPPORT_TEST_WEBKIT_PLATFORM_SUPPORT_H_
 #define WEBKIT_SUPPORT_TEST_WEBKIT_PLATFORM_SUPPORT_H_
 
 #include "base/compiler_specific.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGamepads.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
@@ skipping 66 matching lines @@
 
   virtual WebKit::WebIDBFactory* idbFactory();
 
 #if defined(OS_WIN) || defined(OS_MACOSX)
   void SetThemeEngine(WebKit::WebThemeEngine* engine);
   virtual WebKit::WebThemeEngine *themeEngine();
 #endif
 
   virtual WebKit::WebGraphicsContext3D* createOffscreenGraphicsContext3D(
       const WebKit::WebGraphicsContext3D::Attributes&);
+  virtual WebKit::WebGraphicsContext3D* sharedOffscreenGraphicsContext3D();
   virtual bool canAccelerate2dCanvas();
 
   WebURLLoaderMockFactory* url_loader_factory() {
     return &url_loader_factory_;
   }
 
   const base::FilePath& file_system_root() const {
     return file_system_root_.path();
   }
 
@@ skipping 58 matching lines @@
   WebKit::Platform* shadow_platform_delegate_;
   HyphenDict* hyphen_dictionary_;
 
 #if defined(OS_WIN) || defined(OS_MACOSX)
   WebKit::WebThemeEngine* active_theme_engine_;
 #endif
   DISALLOW_COPY_AND_ASSIGN(TestWebKitPlatformSupport);
 };
 
 #endif  // WEBKIT_SUPPORT_TEST_WEBKIT_PLATFORM_SUPPORT_H_