Impl mus::mojom::GpuService to enable using Chrome IPC version gpu CmdBuf in mus

components/mus/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 "components/mus/gpu/gpu_service_impl.h"
+
+#include "components/mus/common/gpu_type_converters.h"
+#include "components/mus/gpu/gpu_service_mus.h"
+#include "services/shell/public/cpp/connection.h"
+
+namespace mus {
+
+GpuServiceImpl::GpuServiceImpl(
+    mojo::InterfaceRequest<mojom::GpuService> request,
+    shell::Connection* connection)
+    : binding_(this, std::move(request)),
+      client_id_(connection->GetRemoteInstanceID() + 1) {

[Fady Samuel, 2016/05/25 17:06:47]

What is this client ID? A comment would be helpful to explain what it's used
for.

[Peng, 2016/05/25 19:42:55]

The unique client id is for constructing the GpuChannel. I added comment in
header file.

+  // Make sure client_id is greater than 1, because 1 is used for the local
+  // GpuChannel.
+  DCHECK_GT(client_id_, 1);
+}
+
+GpuServiceImpl::~GpuServiceImpl() {}
+
+void GpuServiceImpl::EstablishGpuChannel(
+    bool preempts,
+    bool allow_view_command_buffers,
+    bool allow_real_time_streams,
+    const mojom::GpuService::EstablishGpuChannelCallback& callback) {
+  GpuServiceMus* service = GpuServiceMus::GetInstance();
+  IPC::ChannelHandle channel_handle = service->EstablishGpuChannel(
+      client_id_, client_id_, preempts, allow_view_command_buffers,
+      allow_real_time_streams);

[piman, 2016/05/24 22:46:53]

I think it would be preferable to have EstablishGpuChannel be asynchronous,
taking a callback to pass back the channel handle (and GPU info etc.) -
otherwise here you have to serialize all the clients, which would likely impact
startup time.

[Peng, 2016/05/25 19:42:55]

Done.

+  // TODO(penghuang): Send the GPUInfo to the client.
+  callback.Run(client_id_, mojom::ChannelHandle::From(channel_handle), nullptr);
+}
+
+void GpuServiceImpl::CreateGpuMemoryBuffer(
+    mojom::GpuMemoryBufferIdPtr id,
+    mojo::SizePtr size,
+    mojom::BufferFormat format,
+    mojom::BufferUsage usage,
+    uint64_t surface_id,
+    const mojom::GpuService::CreateGpuMemoryBufferCallback& callback) {
+  NOTIMPLEMENTED();
+}
+
+void GpuServiceImpl::CreateGpuMemoryBufferFromHandle(
+    mojom::GpuMemoryBufferHandlePtr buffer_handle,
+    mojom::GpuMemoryBufferIdPtr id,
+    mojo::SizePtr size,
+    mojom::BufferFormat format,
+    const mojom::GpuService::CreateGpuMemoryBufferFromHandleCallback&
+        callback) {
+  NOTIMPLEMENTED();
+}
+
+void GpuServiceImpl::DestroyGpuMemoryBuffer(mojom::GpuMemoryBufferIdPtr id,
+                                            const gpu::SyncToken& sync_token) {
+  NOTIMPLEMENTED();
+}
+
+}  // namespace mus