Check that |gpu_channel_host_| is not NULL before passing it along.

content/renderer/render_thread_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 "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 1431 matching lines @@
   }
   if (gpu_va_context_provider_.get()) {
     bool enable_video_accelerator =
         !cmd_line->HasSwitch(switches::kDisableAcceleratedVideoDecode);
     std::string image_texture_target_string =
         cmd_line->GetSwitchValueASCII(switches::kContentImageTextureTarget);
     unsigned image_texture_target = 0;
     bool parsed_image_texture_target =
         base::StringToUint(image_texture_target_string, &image_texture_target);
     DCHECK(parsed_image_texture_target);
+    CHECK(gpu_channel_host.get()) << "Have gpu_va_context_provider but no "
+                                     "gpu_channel_host. See crbug.com/495185.";
     gpu_factories = RendererGpuVideoAcceleratorFactories::Create(
         gpu_channel_host.get(), media_task_runner, gpu_va_context_provider_,
         image_texture_target, enable_video_accelerator);
   }
   return gpu_factories;
 }
 
 scoped_ptr<WebGraphicsContext3DCommandBufferImpl>
 RenderThreadImpl::CreateOffscreenContext3d() {
   blink::WebGraphicsContext3D::Attributes attributes(GetOffscreenAttribs());
@@ skipping 571 matching lines @@
 }
 
 void RenderThreadImpl::PendingRenderFrameConnect::OnConnectionError() {
   size_t erased =
       RenderThreadImpl::current()->pending_render_frame_connects_.erase(
           routing_id_);
   DCHECK_EQ(1u, erased);
 }
 
 }  // namespace content