Cast: Added missing DCHECKs to ThreadChecker calls and minor cleanup.

media/cast/audio_receiver/audio_receiver.cc

 // Copyright 2013 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/audio_receiver/audio_receiver.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_piece.h"
@@ skipping 77 matching lines @@
 
  private:
   RtpReceiver* rtp_receiver_;
 };
 
 AudioReceiver::AudioReceiver(scoped_refptr<CastEnvironment> cast_environment,
                              const AudioReceiverConfig& audio_config,
                              transport::PacedPacketSender* const packet_sender)
     : cast_environment_(cast_environment),
       event_subscriber_(
-          cast_environment->GetMessageSingleThreadTaskRunnerForThread(
-              CastEnvironment::MAIN),
           kMaxEventSubscriberEntries,
           ReceiverRtcpEventSubscriber::kAudioEventSubscriber),
       codec_(audio_config.codec),
       frequency_(audio_config.frequency),
       audio_buffer_(),
       audio_decoder_(),
       time_offset_(),
       weak_factory_(this) {
   target_delay_delta_ =
       base::TimeDelta::FromMilliseconds(audio_config.rtp_max_delay_ms);
@@ skipping 390 matching lines @@
   }
   if (audio_decoder_) {
     // Will only send a message if it is time.
     audio_decoder_->SendCastMessage();
   }
   ScheduleNextCastMessage();
 }
 
 }  // namespace cast
 }  // namespace media