Verify GpuService During FrameSink Creation

services/ui/gpu/gpu_main.cc

 // Copyright 2016 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 "services/ui/gpu/gpu_main.h"
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/power_monitor/power_monitor_device_source.h"
@@ skipping 148 matching lines @@
 
   gpu_service_ = base::MakeUnique<GpuService>(
       gpu_init_->gpu_info(), gpu_init_->TakeWatchdogThread(), io_runner,
       gpu_init_->gpu_feature_info());
 }
 
 void GpuMain::CreateFrameSinkManagerInternal(
     cc::mojom::FrameSinkManagerRequest request,
     cc::mojom::FrameSinkManagerClientPtrInfo client_info) {
   DCHECK(!gpu_command_service_);
+  DCHECK(gpu_service_);
   gpu_command_service_ = new gpu::GpuInProcessThreadService(
       gpu_thread_task_runner_, gpu_service_->sync_point_manager(),
       gpu_service_->mailbox_manager(), gpu_service_->share_group());
 
   gpu::ImageFactory* image_factory = gpu_service_->gpu_image_factory();
   mojom::GpuServicePtr gpu_service;
   mojom::GpuServiceRequest gpu_service_request(&gpu_service);
 
   if (gpu_thread_task_runner_->BelongsToCurrentThread()) {
     // If the FrameSinkManager creation was delayed because GpuService had not
@@ skipping 75 matching lines @@
   // TODO(sad): https://crbug.com/645602
 }
 
 bool GpuMain::EnsureSandboxInitialized(
     gpu::GpuWatchdogThread* watchdog_thread) {
   // TODO(sad): https://crbug.com/645602
   return true;
 }
 
 }  // namespace ui