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

components/mus/public/interfaces/gpu_service.mojom

 // 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.
 
 module mus.mojom;
 
 import "components/mus/public/interfaces/channel_handle.mojom";
 import "components/mus/public/interfaces/gpu.mojom";
 import "components/mus/public/interfaces/gpu_memory_buffer.mojom";
 import "gpu/ipc/common/sync_token.mojom";
 import "ui/mojo/geometry/geometry.mojom";
 
 interface GpuService {
   // Tells the GPU service to create a new channel for communication with a
   // client. The GPU service responds asynchronously with IPC handle and
   // GPUInfo.
-  EstablishGpuChannel(bool prempts,
+  EstablishGpuChannel(bool preempts,
                       bool allow_view_command_buffers,
                       bool allow_real_time_streams)

[piman, 2016/05/24 22:46:54]

These 3 bools are security-sensitive. In Chrome we only allow the (trusted)
browser channel to have this on, which we do by making sure the renderer's
requests set this to false.

In the case of mus, the equivalent to the browser channel is I think the
GpuServiceMus's GpuChannelHost which connects directly without the mojom. So I
think these 3 bools should just be removed from the interface, and have the
GpuServiceImpl set those to false for the requests it processes.

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

Could we split this off to two interfaces? Mus Window server will be in a
separate (privileged) process and will likely want to control the same
parameters the browser process does today.

[Peng, 2016/05/25 19:42:56]

I think we could add the private interface later(when we need it). A TODO has
been added in impl.cc

[Peng, 2016/05/25 19:42:56]

Done.

-      => (ChannelHandle channel_handle, GpuInfo gpu_info);
+      => (int32 client_id, ChannelHandle channel_handle, GpuInfo? gpu_info);
 
   // Tells the GPU service to create a new GPU memory buffer.
   CreateGpuMemoryBuffer(GpuMemoryBufferId id,
                         mojo.Size size,
                         BufferFormat format,
                         BufferUsage usage,
                         uint64 surface_id)
       => (GpuMemoryBufferHandle buffer_handle);
 
   // Tells the GPU service to create a new GPU memory buffer from an existing
   // handle.
   CreateGpuMemoryBufferFromHandle(
       GpuMemoryBufferHandle buffer_handle,
       GpuMemoryBufferId id,
       mojo.Size size,
       BufferFormat format) => (GpuMemoryBufferHandle buffer_handle);
 
   // Tells the GPU process to destroy GPU memory buffer.
   DestroyGpuMemoryBuffer(GpuMemoryBufferId id,
                          gpu.mojom.SyncToken sync_token);
 };