services/ui: Introduce mojom.GpuServiceInternal.

services/ui/gpu/interfaces/gpu_service_internal.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 ui.mojom;
+
+import "gpu/ipc/common/gpu_info.mojom";
+
+interface GpuServiceInternal {
+  Initialize() => (gpu.mojom.GpuInfo gpu_info);
+
+  // Tells the GPU service to create a new channel for communication with a
+  // client. The GPU service responds with client ID, IPC handle and
+  // GPUInfo.

[sky, 2016/08/24 20:36:56]

Update this as GpuInfo comes from Initialize. Is there a reason you need a
separate Initialize() and not a single EstablishGpuChannel that does the
implicit initialize?

[sadrul, 2016/08/24 21:17:40]

Updated the doc.

EstablishGpuChannel() is called once for each client, but Initialize() needs to
happen just once.

+  EstablishGpuChannel() => (int32 client_id,
+                            handle<message_pipe> channel_handle);
+};