Remove WebGLObject maps from WebGLRenderingContextBase and WebGLContextGroup.

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

 // 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.
 
 #include "modules/webgl/WebGLFenceSync.h"
 
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "modules/webgl/WebGL2RenderingContextBase.h"
 
 namespace blink {
 
 WebGLSync* WebGLFenceSync::create(WebGL2RenderingContextBase* ctx,
                                   GLenum condition,
                                   GLbitfield flags) {
   return new WebGLFenceSync(ctx, condition, flags);
 }
 
-WebGLFenceSync::~WebGLFenceSync() {}
-
 WebGLFenceSync::WebGLFenceSync(WebGL2RenderingContextBase* ctx,
                                GLenum condition,
                                GLbitfield flags)
     : WebGLSync(ctx,
                 ctx->contextGL()->FenceSync(condition, flags),
                 GL_SYNC_FENCE) {}
 
 }  // namespace blink