cc: Add null checks for GrContext created by ContextProviderCommandBuffer.

content/common/gpu/client/context_provider_command_buffer.cc

 // Copyright (c) 2013 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 "content/common/gpu/client/context_provider_command_buffer.h"
 
 #include <set>
 #include <vector>
 
 #include "base/callback_helpers.h"
@@ skipping 119 matching lines @@
 class GrContext* ContextProviderCommandBuffer::GrContext() {
   DCHECK(lost_context_callback_proxy_);  // Is bound to thread.
   DCHECK(context_thread_checker_.CalledOnValidThread());
 
   if (gr_context_)
     return gr_context_->get();
 
   gr_context_.reset(new GrContextForWebGraphicsContext3D(context3d_.get()));
 
   // If GlContext is already lost, also abandon the new GrContext.
-  if (IsContextLost())
+  if (gr_context_->get() && IsContextLost())
     gr_context_->get()->abandonContext();
 
   return gr_context_->get();
 }
 
 void ContextProviderCommandBuffer::InvalidateGrContext(uint32_t state) {
   if (gr_context_) {
     DCHECK(lost_context_callback_proxy_);  // Is bound to thread.
     DCHECK(context_thread_checker_.CalledOnValidThread());
     gr_context_->get()->resetContext(state);
@@ skipping 92 matching lines @@
 
 void ContextProviderCommandBuffer::SetMemoryPolicyChangedCallback(
     const MemoryPolicyChangedCallback& memory_policy_changed_callback) {
   DCHECK(context_thread_checker_.CalledOnValidThread());
   DCHECK(memory_policy_changed_callback_.is_null() ||
          memory_policy_changed_callback.is_null());
   memory_policy_changed_callback_ = memory_policy_changed_callback;
 }
 
 }  // namespace content