Media Remoting: Data/Control plumbing between renderer and Media Router.

chrome/browser/media/cast_remoting_sender.h

+// 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.
+
+#ifndef CHROME_BROWSER_MEDIA_CAST_REMOTING_SENDER_H_
+#define CHROME_BROWSER_MEDIA_CAST_REMOTING_SENDER_H_
+
+#include "base/callback_forward.h"
+#include "base/memory/weak_ptr.h"
+#include "media/mojo/interfaces/remoting.mojom.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+// RTP sender for a single Cast Remoting RTP stream. The client calls Send() to
+// instruct the sender to read from a Mojo data pipe and transmit the data using
+// a CastTransport. This entire class executes on the IO BrowserThread.
+//
+// This class is instantiated and owned by CastTransportHostFilter in response
+// to IPC messages from an extension process to create RTP streams for the media
+// remoting use case. CastTransportHostFilter is also responsible for destroying
+// the instance in response to later IPCs.
+//
+// The Media Router provider extension controls the entire set-up process:
+// First, it uses the cast.streaming APIs to create remoting API streams (which
+// instantiates one or more CastRemotingSenders). Then, it sends a message via
+// Media Router to a CastRemotingConnector to indicate the bitstream transport
+// is ready. Finally, CastRemotingConnector calls FindAndBind() to look-up the
+// CastRemotingSender instances and establish the Mojo bindings and data flows.
+//
+// TODO(miu): Merge with CastRemotingSender from xjz's recent change.
+class CastRemotingSender : public media::mojom::RemotingDataStreamSender {
+ public:
+  explicit CastRemotingSender(int32_t rtp_stream_id);
+  ~CastRemotingSender() final;
+
+  // Look-up a CastRemotingSender instance by its |rtp_stream_id| and then bind
+  // to the given |request|. The client of the RemotingDataStreamSender will
+  // then instruct this CastRemotingSender when to read from the data |pipe| and
+  // send the data to the Cast Receiver. If the bind fails, or an error occurs
+  // reading from the data pipe during later operation, the |error_callback| is
+  // run.
+  //
+  // Threading note: This function is thread-safe, but its internal
+  // implementation runs on the IO BrowserThread. If |error_callback| is run, it
+  // will execute on the thread that called this function.
+  static void FindAndBind(int32_t rtp_stream_id,
+                          mojo::ScopedDataPipeConsumerHandle pipe,
+                          media::mojom::RemotingDataStreamSenderRequest request,
+                          const base::Closure& error_callback);
+
+ private:
+  // media::mojom::RemotingDataStreamSender implementation.
+  void ConsumeDataChunk(uint32_t offset, uint32_t size,
+                        uint32_t total_payload_size) final;
+  void SendFrame() final;
+  void CancelInFlightData() final;
+
+  const int32_t rtp_stream_id_;
+  mojo::Binding<RemotingDataStreamSender> binding_;
+  base::Closure error_callback_;
+  mojo::ScopedDataPipeConsumerHandle pipe_;
+
+  // The next frame's payload data. Populated by one or more calls to
+  // ConsumeDataChunk().
+  std::string next_frame_data_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastRemotingSender);
+};
+
+#endif  // CHROME_BROWSER_MEDIA_CAST_REMOTING_SENDER_H_