Media Remoting: Add mojo interfaces between browser and extension.

media/mojo/interfaces/mirror_service_remoting.mojom

Index: media/mojo/interfaces/mirror_service_remoting.mojom
diff --git a/media/mojo/interfaces/remoting.mojom b/media/mojo/interfaces/mirror_service_remoting.mojom
similarity index 11%
copy from media/mojo/interfaces/remoting.mojom
copy to media/mojo/interfaces/mirror_service_remoting.mojom
index ba218f31f3791e91c28e72f83bbd2f297792ecd1..a762dbf5c1f18fa67ddcdfbb8fe6cb4b16446757 100644
--- a/media/mojo/interfaces/remoting.mojom
+++ b/media/mojo/interfaces/mirror_service_remoting.mojom
@@ -1,126 +1,52 @@
-// Copyright 2016 The Chromium Authors. All rights reserved.
+// 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;
 
-interface RemoterFactory {
-  // Create a new Remoter associated with the given RemotingSource and bind it
-  // to the given interface request. The RemotingSource will be notified when
-  // the Remoter becomes available for use (or becomes unavailable).
-  Create(RemotingSource source, Remoter& remoter);
-};
-
-// Interface used by the source to control when media bitstream data is read
-// from a data pipe and then sent to the remote endpoint. There is one
-// RemotingDataStreamSender per data pipe.
-interface RemotingDataStreamSender {
-  // Consumes |size| bytes of data from the data pipe, which is a chunk of the
-  // next frame's data payload starting at the given byte |offset|.
-  // |total_payload_size| indicates the size of the entire data payload for the
-  // frame. Before this is called, |size| bytes of data must have been written
-  // into the data pipe.
-  //
-  // Normally, a frame's entire data payload can be pushed through the data pipe
-  // in one chunk. However, there can be situations where the size of the
-  // payload exceeds the capacity of the data pipe; and so this API supports
-  // feeding the frame data through the pipe in multiple chunks.
-  ConsumeDataChunk(uint32 offset, uint32 size, uint32 total_payload_size);
-
-  // Enqueues another frame for transmission to the remote endpoint. Before this
-  // is called, ConsumeDataChunk() must have been called one or more times to
-  // provide all of the frame's data.
-  SendFrame();
-
-  // Cancel the transmission of all in-flight data to the remote, up to and
-  // including the last SendFrame() call; and also discard any data chunks
-  // that were consumed from the data pipe for the next frame. This is used to
-  // optimize seeking, when it is known that any in-flight data is no longer
-  // needed by the remote. There is no guarantee as to how much of the in-flight
-  // data will actually reach the remote before the cancellation takes effect.
-  CancelInFlightData();
-};
-
-enum RemotingStopReason {
-  ROUTE_TERMINATED,  // User-initiated disconnect, etc.
-  LOCAL_PLAYBACK,  // Media switched back to local playback.
-  SOURCE_GONE,  // RemotingSource has been destroyed.
-  MESSAGE_SEND_FAILED,  // Failed to send a message to the sink.
-  DATA_SEND_FAILED,  // Failed to consume from a data pipe or send to the sink.
-  UNEXPECTED_FAILURE,  // Unexpected failure or inconsistent state encountered.
-};
+import "media/mojo/interfaces/remoting_common.mojom";
 
 // Interface used by the source to start/stop remoting and send data to the
 // sink.
-interface Remoter {
-  // Start a remoting session (once the sink has been reported to be available;
-  // see RemotingSource). Either RemotingSource.OnStarted() or OnStartFailed()
-  // will be called to indicate success or failure. Once OnStarted() has been
-  // invoked, the source may then make calls to SendMessageToSink() and expect
-  // messages from the remote via RemotingSource.OnMessageFromSink().
+interface MirrorServiceRemoter {
+  // Starts a remoting session. Always assumes the remoting session will be
+  // stared successfully. If any failure happens,
+  // MirrorServiceRemotingSource::OnError() will be called.
   Start();
 
-  // Start remoting the media data streams. This is called after Start() to
-  // provide data pipes from which the audio/video bitstream data is consumed
-  // and then transported to the remote device. RemotingDataStreamSenders are
-  // used by the source to control when data should be consumed from the data
-  // pipes and sent. One or both pipes (and their corresponding
-  // RemotingDataStreamSender interface requests) must be provided.
-  StartDataStreams(handle<data_pipe_consumer>? audio_pipe,
-                   handle<data_pipe_consumer>? video_pipe,
-                   RemotingDataStreamSender&? audio_sender,
-                   RemotingDataStreamSender&? video_sender);
+  // Starts remoting the media data streams. This is called after Start() to
+  // indicate audio/video bitstream data is ready to be consumed.
+  StartDataStreams(bool has_audio, bool has_video)
+      => (int32 audio_stream_id, int32 video_stream_id);

[Robert Sesek, 2017/07/06 23:24:15]

What does this return if one or both of the booleans are false?

[xjz, 2017/07/07 00:14:58]

The stream ID will be -1. Added comments.

 
-  // Stop remoting media. Messages in both directions will be dropped after this
-  // point as well as any pending or in-transit media bitstream data.
+  // Stops remoting media. Messages in both directions will be dropped after
+  // this point as well as any pending or in-transit media bitstream data.
   Stop(RemotingStopReason reason);
 
-  // Send |message| to the sink. |message| is a serialized protobuf from
+  // Sends|message| to the sink. |message| is a serialized protobuf from
   // src/media/remoting/proto.
   SendMessageToSink(array<uint8> message);
 };
 
-enum RemotingSinkCapabilities {
-  NONE,
-  RENDERING_ONLY,
-  CONTENT_DECRYPTION_AND_RENDERING,
-};
-
-enum RemotingStartFailReason {
-  CANNOT_START_MULTIPLE,  // Remoting was already active.
-  ROUTE_TERMINATED,  // User-initated disconnect while starting remoting.
-};
-
-// Interface used for sending notifications back to the local source's control
-// logic, and to pass messages from the sink back to the local media pipeline.
-interface RemotingSource {
-  // Notify the source that the sink is now available to start remoting. It is
-  // up to the source's control logic to decide whether/when to start remoting.
-  //
-  // TODO(miu): In a later change, pass detailed information about the sink's
-  // capabilities (e.g., codec support, DRM keysystem support, etc.).
-  OnSinkAvailable(RemotingSinkCapabilities capabilities);
+// Interface used for sending notifications back to the source's control logic,
+// and to pass messages from the sink back to the source.
+interface MirrorServiceRemotingSource {
+  // Notifies the source that the sink is now available to start remoting and
+  // passes the receiver's capabilities. It is up to the source's control logic
+  // to decide whether/when to start remoting.
+  OnSinkAvailable(SinkCapabilities capabilities);
 
-  // Notify the source that the sink is no longer available for remoting. This
-  // may happen, for example, because the sink has been shut down, or because
-  // another source has started remoting.
-  OnSinkGone();
-
-  // One of these is called after the source attempts to start remoting. If
-  // OnStarted() is called, messages may begin flowing; and this will continue
-  // until OnStopped() is called. On the other hand, if OnStartFailed() is
-  // called, then no messages are being passed between source and sink and
-  // remoting is not taking place.
-  OnStarted();
-  OnStartFailed(RemotingStartFailReason reason);
-
-  // Pass a |message| from the sink back to the source. The |message| consists
+  // Passes a |message| from the sink back to the source. The |message| consists
   // of a serialized protobuf from src/media/remoting/proto. This will only be
   // called after OnStarted() and before OnStopped().
   OnMessageFromSink(array<uint8> message);
 
-  // Notify the source that remoting has terminated. This may or may not be in
+  // Notifies the source that remoting has terminated. This may or may not be in
   // response to a Remoter.Stop() call, as other events (possibly external) may
   // have caused remoting to end.
   OnStopped(RemotingStopReason reason);
+
+  // Notifies the source that a fatal error has occurred. Remoting session will
+  // be stopped immediately once this is called.

[Robert Sesek, 2017/07/06 23:24:15]

Does OnStopped get delivered too?

[xjz, 2017/07/07 00:14:58]

OnStopped() might be called later, but not always. OnStopped() is either in
response to a MirrorServiceRemoter.Stop() call or some events (e.g. user stops
casting). The current data flow is when any error occurs, OnError() is called to
notify the source and the source will stop remoting immediately. If the
MirrorServiceRemoter is still connected to the source, it receivers the Stop()
request and will call OnStopped() later. But if the MirrorServiceRemoter is
disconnected after error occurs, OnStopped() will not be called.

+  OnError();

[Robert Sesek, 2017/07/06 23:24:15]

Should there be an error code?

[xjz, 2017/07/07 00:14:58]

There are no error codes right now. It is currently called from Media Router
extension, and the error message is logged out. We might add error codes later
with some refactoring. Added a TODO comment.

 };