services/ui: Get rid of IPC::ChannelHandle type converter

services/ui/gpu/gpu_service_mus.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_service_mus.h"
 
 #include "base/memory/shared_memory.h"
 #include "base/memory/singleton.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 24 matching lines @@
 #endif
 
 namespace ui {
 namespace {
 
 const int kLocalGpuChannelClientId = 1;
 const uint64_t kLocalGpuChannelClientTracingId = 1;
 
 void EstablishGpuChannelDone(
     int client_id,
-    const IPC::ChannelHandle* channel_handle,
+    IPC::ChannelHandle* channel_handle,
     const GpuServiceMus::EstablishGpuChannelCallback& callback) {
-  callback.Run(channel_handle ? client_id : -1, *channel_handle);
+  callback.Run(channel_handle ? client_id : -1, channel_handle);
 }
 }
 
 GpuServiceMus::GpuServiceMus()
     : next_client_id_(kLocalGpuChannelClientId),
       main_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       shutdown_event_(base::WaitableEvent::ResetPolicy::MANUAL,
                       base::WaitableEvent::InitialState::NOT_SIGNALED),
       gpu_thread_("GpuThread"),
       io_thread_("GpuIOThread") {
@@ skipping 11 matching lines @@
 
 void GpuServiceMus::EstablishGpuChannel(
     uint64_t client_tracing_id,
     bool preempts,
     bool allow_view_command_buffers,
     bool allow_real_time_streams,
     const EstablishGpuChannelCallback& callback) {
   DCHECK(CalledOnValidThread());
 
   if (!gpu_channel_manager_) {
-    callback.Run(-1, IPC::ChannelHandle());
+    callback.Run(-1, nullptr);

[dcheng, 2016/08/18 00:06:01]

I would probably just throw a IPC::ChannelHandle on the stack here and pass the
address to the callback. Then we shouldn't need to handle the null case in
either of the callbacks, simplifying everything overall.

     return;
   }
 
   const int client_id = ++next_client_id_;
   IPC::ChannelHandle* channel_handle = new IPC::ChannelHandle;
   gpu_thread_.task_runner()->PostTaskAndReply(
       FROM_HERE,
       base::Bind(&GpuServiceMus::EstablishGpuChannelOnGpuThread,
                  base::Unretained(this), client_id, client_tracing_id, preempts,
                  allow_view_command_buffers, allow_real_time_streams,
@@ skipping 176 matching lines @@
   return shm;
 }
 
 // static
 GpuServiceMus* GpuServiceMus::GetInstance() {
   return base::Singleton<GpuServiceMus,
                          base::LeakySingletonTraits<GpuServiceMus>>::get();
 }
 
 }  // namespace ui