Test context_->GetCommandBufferProxy() before following it blindly.

content/renderer/media/renderer_gpu_video_decoder_factories.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 "content/renderer/media/renderer_gpu_video_decoder_factories.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 
 #include "base/bind.h"
@@ skipping 49 matching lines @@
   waiter.Wait();
   return vda;
 }
 
 void RendererGpuVideoDecoderFactories::AsyncCreateVideoDecodeAccelerator(
       media::VideoCodecProfile profile,
       media::VideoDecodeAccelerator::Client* client,
       media::VideoDecodeAccelerator** vda,
       base::WaitableEvent* waiter) {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
-  if (context_) {
+  if (context_ && context_->GetCommandBufferProxy()) {
     *vda = gpu_channel_host_->CreateVideoDecoder(
         context_->GetCommandBufferProxy()->GetRouteID(),
         profile, client);
   } else {
     *vda = NULL;
   }
   waiter->Signal();
 }
 
 bool RendererGpuVideoDecoderFactories::CreateTextures(
@@ skipping 71 matching lines @@
   waiter.Wait();
   return shm;
 }
 
 void RendererGpuVideoDecoderFactories::AsyncCreateSharedMemory(
     size_t size, base::SharedMemory** shm, base::WaitableEvent* waiter) {
   DCHECK_EQ(MessageLoop::current(), ChildThread::current()->message_loop());
   *shm = ChildThread::current()->AllocateSharedMemory(size);
   waiter->Signal();
 }