services/ui: Have an explicit lifetime/ownership of ui::GpuService.

services/ui/common/gpu_service.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/common/gpu_service.h"
 
 #include "base/command_line.h"
 #include "base/memory/singleton.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
@@ skipping 29 matching lines @@
       establishing_condition_(&lock_) {
   DCHECK(main_task_runner_);
   DCHECK(connector_);
   base::Thread::Options thread_options(base::MessageLoop::TYPE_IO, 0);
   thread_options.priority = base::ThreadPriority::NORMAL;
   CHECK(io_thread_.StartWithOptions(thread_options));
 }
 
 GpuService::~GpuService() {
   DCHECK(IsMainThread());
+  DCHECK_EQ(this, g_gpu_service);
   if (gpu_channel_)
     gpu_channel_->DestroyChannel();
-}
-
-// static
-void GpuService::Initialize(shell::Connector* connector) {
-  DCHECK(!g_gpu_service);
-  g_gpu_service = new GpuService(connector);
-}
-
-// static
-void GpuService::Terminate() {
-  DCHECK(g_gpu_service);
-  delete g_gpu_service;
   g_gpu_service = nullptr;
 }
 
 // static
+std::unique_ptr<GpuService> GpuService::Initialize(
+    shell::Connector* connector) {
+  DCHECK(!g_gpu_service);
+  g_gpu_service = new GpuService(connector);
+  return base::WrapUnique(g_gpu_service);
+}
+
+// static
 GpuService* GpuService::GetInstance() {
   DCHECK(g_gpu_service);
   return g_gpu_service;
 }
 
 void GpuService::EstablishGpuChannel(const base::Closure& callback) {
   base::AutoLock auto_lock(lock_);
   auto runner = base::ThreadTaskRunnerHandle::Get();
   if (GetGpuChannelLocked()) {
     runner->PostTask(FROM_HERE, callback);
@@ skipping 154 matching lines @@
   MojoResult result = mojo::UnwrapSharedMemoryHandle(
       std::move(handle), &platform_handle, &shared_memory_size, &readonly);
   if (result != MOJO_RESULT_OK)
     return nullptr;
   DCHECK_EQ(shared_memory_size, size);
 
   return base::MakeUnique<base::SharedMemory>(platform_handle, readonly);
 }
 
 }  // namespace ui