Remove WebGLObject maps from WebGLRenderingContextBase and WebGLContextGroup.

third_party/WebKit/Source/modules/webgl/WebGLFenceSync.h

 // Copyright 2015 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 WebGLFenceSync_h
 #define WebGLFenceSync_h
 
 #include "modules/webgl/WebGLSync.h"
 
 namespace blink {
 
 class WebGL2RenderingContextBase;
 
 class WebGLFenceSync : public WebGLSync {
  public:
-  ~WebGLFenceSync() override;
-
   static WebGLSync* create(WebGL2RenderingContextBase*,
                            GLenum condition,
                            GLbitfield flags);
 
  protected:
   WebGLFenceSync(WebGL2RenderingContextBase*,
                  GLenum condition,
                  GLbitfield flags);
 };
 
 }  // namespace blink
 
 #endif  // WebGLFenceSync_h