Mojify demuxers and allow running {Chunk/FFmpeg}Demuxer in a Utility Process

media/mojo/interfaces/data_source.mojom

+// Copyright 2017 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 media.mojom;
+
+import "media/mojo/interfaces/media_types.mojom";
+import "mojo/common/time.mojom";
+
+interface DataSource {
+  Initialize() => (handle<data_pipe_consumer> pipe);
+
+  Read(int64 position, int32 size) => (DataBuffer? buffer, int32 size);
+
+  Stop();
+
+  Abort();
+
+  [Sync]
+  GetSize() => (bool success, int64 size);
+
+  [Sync]
+  IsStreaming() => (bool is_streaming);
+
+  SetBitrate(int32 bitrate);
+};