Update from https://crrev.com/309717

gpu/blink/webgraphicscontext3d_impl.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/blink/webgraphicscontext3d_impl.h"
 
 #include "base/atomicops.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "gpu/GLES2/gl2extchromium.h"
@@ skipping 23 matching lines @@
 } // namespace anonymous
 
 class WebGraphicsContext3DErrorMessageCallback
     : public ::gpu::gles2::GLES2ImplementationErrorMessageCallback {
  public:
   WebGraphicsContext3DErrorMessageCallback(
       WebGraphicsContext3DImpl* context)
       : graphics_context_(context) {
   }
 
-  virtual void OnErrorMessage(const char* msg, int id) override;
+  void OnErrorMessage(const char* msg, int id) override;
 
  private:
   WebGraphicsContext3DImpl* graphics_context_;
 
   DISALLOW_COPY_AND_ASSIGN(WebGraphicsContext3DErrorMessageCallback);
 };
 
 void WebGraphicsContext3DErrorMessageCallback::OnErrorMessage(
     const char* msg, int id) {
   graphics_context_->OnErrorMessage(msg, id);
@@ skipping 966 matching lines @@
   output_attribs->depth_size = attributes.depth ? 24 : 0;
   output_attribs->stencil_size = attributes.stencil ? 8 : 0;
   output_attribs->samples = attributes.antialias ? 4 : 0;
   output_attribs->sample_buffers = attributes.antialias ? 1 : 0;
   output_attribs->fail_if_major_perf_caveat =
       attributes.failIfMajorPerformanceCaveat;
   output_attribs->bind_generates_resource = false;
 }
 
 }  // namespace gpu_blink