Implement GpuArcVideoService::AcceleratorStub using mojo

components/arc/common/video_accelerator.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 arc;
+
+[Client=VideoAcceleratorServiceClient]
+
+enum HalPixelFormatExtension {
+  HAL_PIXEL_FORMAT_H264 = 0x34363248,
+  HAL_PIXEL_FORMAT_VP8 = 0x00385056,
+};
+
+enum PortType {
+  PORT_INPUT = 0,
+  PORT_OUTPUT = 1,
+};
+
+// TODO(kcwu): move into VideoAcceleratorService
+enum DeviceType {
+  DEVICE_ENCODER = 0,
+  DEVICE_DECODER = 1,
+};
+
+// TODO(kcwu): move into BufferFormat
+enum MemoryType {
+  MEMORY_SHARED_MEMORY = 1,
+  MEMORY_DMABUF = 2,
+};
+
+enum BufferFlag {
+  BUFFER_FLAG_EOS = 1,
+};
+
+struct BufferMetadata {
+  int64 timestamp;  // in microseconds
+  uint32 flags;
+  uint32 bytes_used;
+};
+
+struct BufferFormat {
+  uint32 pixel_format;  // the v4l2 fourcc format
+  MemoryType memory_type;
+};
+
+struct VideoFormat {
+  uint32 pixel_format;
+  uint32 image_size;
+
+  // minimal number of buffers required to process the video.
+  uint32 min_num_buffers;
+  uint32 coded_width;
+  uint32 coded_height;
+  uint32 crop_left;
+  uint32 crop_width;
+  uint32 crop_top;
+  uint32 crop_height;
+};
+
+interface VideoAcceleratorService {
+  Initialize(DeviceType device) => (bool result);
+
+  BindSharedMemory(PortType port, uint32 index, handle ashmem_fd,
+                   uint64 offset, uint64 length) => (bool result);
+
+  BindDmabuf(PortType port, uint32 index, handle dmabuf_fd) => (bool result);
+
+  UseBuffer(PortType port, uint32 index, BufferMetadata metadata);
+
+  SetBufferCount(PortType port, uint64 set_count) => (bool result, uint64 reply_count);
+
+  Reset() => ();
+
+  SetBufferFormat(PortType port, BufferFormat format) => (bool result);
+};
+
+interface VideoAcceleratorServiceClient {
+  enum Error {
+    NO_ERROR = 0,
+    ILLEGAL_STATE = 1,
+    INVALID_ARGUMENT = 2,
+    UNREADABLE_INPUT = 3,
+    PLATFORM_FAILURE = 4,
+  };
+
+  SetService(VideoAcceleratorService service_ptr);
+
+  OnError(Error error);
+
+  OnBufferDone(PortType port, uint32 index, BufferMetadata metadata);
+
+  OnOutputFormatChanged(VideoFormat format);
+};