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

media/cast/receiver/frame_receiver.cc

 // 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.
 
 #include "media/cast/receiver/frame_receiver.h"
 
 #include <algorithm>
 
 #include "base/big_endian.h"
 #include "base/bind.h"
@@ skipping 238 matching lines @@
 
     // At this point, we have a decrypted EncodedFrame ready to be emitted.
     encoded_frame->reference_time = playout_time;
     framer_.ReleaseFrame(encoded_frame->frame_id);
     if (encoded_frame->new_playout_delay_ms) {
       target_playout_delay_ = base::TimeDelta::FromMilliseconds(
           encoded_frame->new_playout_delay_ms);
     }
     cast_environment_->PostTask(CastEnvironment::MAIN,
                                 FROM_HERE,
-                                base::Bind(frame_request_queue_.front(),
+                                base::Bind(&FrameReceiver::EmitOneFrame,
+                                           weak_factory_.GetWeakPtr(),
+                                           frame_request_queue_.front(),
                                            base::Passed(&encoded_frame)));
     frame_request_queue_.pop_front();
   }
 }
 
 void FrameReceiver::EmitAvailableEncodedFramesAfterWaiting() {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   DCHECK(is_waiting_for_consecutive_frame_);
   is_waiting_for_consecutive_frame_ = false;
   EmitAvailableEncodedFrames();
 }
 
+void FrameReceiver::EmitOneFrame(const ReceiveEncodedFrameCallback& callback,
+                                 scoped_ptr<EncodedFrame> encoded_frame) const {
+  DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
+  if (!callback.is_null())
+    callback.Run(encoded_frame.Pass());
+}
+
 base::TimeTicks FrameReceiver::GetPlayoutTime(const EncodedFrame& frame) const {
   base::TimeDelta target_playout_delay = target_playout_delay_;
   if (frame.new_playout_delay_ms) {
     target_playout_delay = base::TimeDelta::FromMilliseconds(
         frame.new_playout_delay_ms);
   }
   return lip_sync_reference_time_ +
       lip_sync_drift_.Current() +
       RtpDeltaToTimeDelta(
           static_cast<int32>(frame.rtp_timestamp - lip_sync_rtp_timestamp_),
@@ skipping 38 matching lines @@
 }
 
 void FrameReceiver::SendNextRtcpReport() {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   rtcp_.SendRtcpFromRtpReceiver(NULL, base::TimeDelta(), NULL, &stats_);
   ScheduleNextRtcpReport();
 }
 
 }  // namespace cast
 }  // namespace media