[Cast] Fix shutdown race between CastReceiverImpl/FrameReceiver and frame emit callback run.

media/cast/receiver/frame_receiver.h

 // Copyright 2014 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 MEDIA_CAST_RECEIVER_FRAME_RECEIVER_H_
 #define MEDIA_CAST_RECEIVER_FRAME_RECEIVER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 71 matching lines @@
   // Processes ready-to-consume packets from |framer_|, decrypting each packet's
   // payload data, and then running the enqueued callbacks in order (one for
   // each packet).  This method may post a delayed task to re-invoke itself in
   // the future to wait for missing/incomplete frames.
   void EmitAvailableEncodedFrames();
 
   // Clears the |is_waiting_for_consecutive_frame_| flag and invokes
   // EmitAvailableEncodedFrames().
   void EmitAvailableEncodedFramesAfterWaiting();
 
+  // Helper that runs |callback|, passing ownership of |encoded_frame| to it.
+  // This method is used by EmitAvailableEncodedFrames() to return to the event
+  // loop, but make sure that FrameReceiver is still alive before the callback
+  // is run.
+  void EmitOneFrame(const ReceiveEncodedFrameCallback& callback,
+                    scoped_ptr<EncodedFrame> encoded_frame) const;
+
   // Computes the playout time for a frame with the given |rtp_timestamp|.
   // Because lip-sync info is refreshed regularly, calling this method with the
   // same argument may return different results.
   base::TimeTicks GetPlayoutTime(const EncodedFrame& frame) const;
 
   // Schedule timing for the next cast message.
   void ScheduleNextCastMessage();
 
   // Schedule timing for the next RTCP report.
   void ScheduleNextRtcpReport();
@@ skipping 76 matching lines @@
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<FrameReceiver> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameReceiver);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_RECEIVER_FRAME_RECEIVER_H_