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

services/ui/gpu/gpu_service_impl.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_impl.h"
 
 #include "services/shell/public/cpp/connection.h"
 #include "services/ui/common/gpu_type_converters.h"
 #include "services/ui/gpu/gpu_service_mus.h"
 
 namespace ui {
 
 namespace {
 
 void EstablishGpuChannelDone(
     const mojom::GpuService::EstablishGpuChannelCallback& callback,
     int32_t client_id,
     const IPC::ChannelHandle& channel_handle) {
   // TODO(penghuang): Send the real GPUInfo to the client.
-  callback.Run(client_id, mojom::ChannelHandle::From(channel_handle),
+  callback.Run(client_id,
+               mojo::ScopedMessagePipeHandle(channel_handle.mojo_handle),

[dcheng, 2016/08/17 19:38:29]

Does ChannelHandle not have strong ownership of its mojo_handle? I'm not
familiar with this part of the system, so I'm trying to understand how it works.

[Peng, 2016/08/17 19:59:17]

IPC::ChannelHandle is more like a data struct instead of class. It doesn't
maintain the life cycle of its members. It is just used for passing data I
think.

In here, the mojo::ScopedMessagePipleHandle() will take the ownership of the
channel_handle.mojo_handle.

                gpu::GPUInfo());
 }
 }
 
 GpuServiceImpl::GpuServiceImpl(
     mojo::InterfaceRequest<mojom::GpuService> request)
     : binding_(this, std::move(request)) {}
 
 GpuServiceImpl::~GpuServiceImpl() {}
 
@@ skipping 22 matching lines @@
     const mojom::GpuService::CreateGpuMemoryBufferCallback& callback) {
   NOTIMPLEMENTED();
 }
 
 void GpuServiceImpl::DestroyGpuMemoryBuffer(mojom::GpuMemoryBufferIdPtr id,
                                             const gpu::SyncToken& sync_token) {
   NOTIMPLEMENTED();
 }
 
 }  // namespace ui