services/ui: Inject GpuService instance where needed, instead of singleton.

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 10 matching lines @@
 namespace {
 
 void PostTask(scoped_refptr<base::SingleThreadTaskRunner> runner,
               const tracked_objects::Location& from_here,
               const gpu::GpuChannelEstablishedCallback& callback,
               scoped_refptr<gpu::GpuChannelHost> established_channel_host) {
   runner->PostTask(from_here,
                    base::Bind(callback, std::move(established_channel_host)));
 }
 
-GpuService* g_gpu_service = nullptr;
 }
 
 GpuService::GpuService(shell::Connector* connector)
     : main_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       connector_(connector),
       shutdown_event_(base::WaitableEvent::ResetPolicy::AUTOMATIC,
                       base::WaitableEvent::InitialState::NOT_SIGNALED),
       io_thread_("GPUIOThread"),
       gpu_memory_buffer_manager_(new MojoGpuMemoryBufferManager),
       is_establishing_(false),
       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();
-  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;
+  return base::WrapUnique(new GpuService(connector));
 }
 
 void GpuService::EstablishGpuChannel(
     const gpu::GpuChannelEstablishedCallback& callback) {
   base::AutoLock auto_lock(lock_);
   auto runner = base::ThreadTaskRunnerHandle::Get();
   scoped_refptr<gpu::GpuChannelHost> channel = GetGpuChannelLocked();
   if (channel) {
     PostTask(runner, FROM_HERE, callback, std::move(channel));
     return;
@@ skipping 148 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