Update from https://crrev.com/316786

mojo/cc/context_provider_mojo.cc

 // Copyright 2014 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 "mojo/cc/context_provider_mojo.h"
 
 #include "base/logging.h"
 #include "mojo/public/cpp/environment/environment.h"
 
 namespace mojo {
@@ skipping 28 matching lines @@
   return static_cast<gpu::ContextSupport*>(
       MojoGLES2GetContextSupport(context_));
 }
 
 class GrContext* ContextProviderMojo::GrContext() { return NULL; }
 
 cc::ContextProvider::Capabilities ContextProviderMojo::ContextCapabilities() {
   return capabilities_;
 }
 
+void ContextProviderMojo::SetupLock() {
+}
+
+base::Lock* ContextProviderMojo::GetLock() {
+  return &context_lock_;
+}
+
 bool ContextProviderMojo::IsContextLost() {
   return context_lost_;
 }
 bool ContextProviderMojo::DestroyedOnMainThread() { return !context_; }
 
 ContextProviderMojo::~ContextProviderMojo() {
   if (context_)
     MojoGLES2DestroyContext(context_);
 }
 
 void ContextProviderMojo::ContextLost() {
   context_lost_ = true;
 }
 
 }  // namespace mojo