[Cast] Repurpose CastInitializationStatus for variable frame size support.

media/cast/sender/audio_sender.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/sender/audio_sender.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/net/cast_transport_config.h"
 #include "media/cast/sender/audio_encoder.h"
 
 namespace media {
 namespace cast {
 
 AudioSender::AudioSender(scoped_refptr<CastEnvironment> cast_environment,
                          const AudioSenderConfig& audio_config,
+                         const StatusChangeCallback& status_change_cb,
                          CastTransportSender* const transport_sender)
     : FrameSender(cast_environment,
                   true,
                   transport_sender,
                   base::TimeDelta::FromMilliseconds(audio_config.rtcp_interval),
                   audio_config.frequency,
                   audio_config.ssrc,
                   0,  // |max_frame_rate_| is set after encoder initialization.
                   audio_config.min_playout_delay,
                   audio_config.max_playout_delay,
                   NewFixedCongestionControl(audio_config.bitrate)),
       samples_in_encoder_(0),
       weak_factory_(this) {
-  cast_initialization_status_ = STATUS_AUDIO_UNINITIALIZED;
-
   if (!audio_config.use_external_encoder) {
     audio_encoder_.reset(
         new AudioEncoder(cast_environment,
                          audio_config.channels,
                          audio_config.frequency,
                          audio_config.bitrate,
                          audio_config.codec,
                          base::Bind(&AudioSender::OnEncodedAudioFrame,
                                     weak_factory_.GetWeakPtr(),
                                     audio_config.bitrate)));
-    cast_initialization_status_ = audio_encoder_->InitializationResult();
-  } else {
-    NOTREACHED();  // No support for external audio encoding.
-    cast_initialization_status_ = STATUS_AUDIO_UNINITIALIZED;
   }
 
+  // AudioEncoder provides no operational status changes during normal use.
+  // Post a task now with its initialization result status to allow the client
+  // to start sending frames.
+  cast_environment_->PostTask(
+      CastEnvironment::MAIN,
+      FROM_HERE,
+      base::Bind(status_change_cb,
+                 audio_encoder_ ? audio_encoder_->InitializationResult() :
+                     STATUS_INVALID_CONFIGURATION));
+
   // The number of samples per encoded audio frame depends on the codec and its
   // initialization parameters. Now that we have an encoder, we can calculate
   // the maximum frame rate.
   max_frame_rate_ =
       audio_config.frequency / audio_encoder_->GetSamplesPerFrame();
 
   media::cast::CastTransportRtpConfig transport_config;
   transport_config.ssrc = audio_config.ssrc;
   transport_config.feedback_ssrc = audio_config.receiver_ssrc;
   transport_config.rtp_payload_type = audio_config.rtp_payload_type;
   transport_config.aes_key = audio_config.aes_key;
   transport_config.aes_iv_mask = audio_config.aes_iv_mask;
 
   transport_sender->InitializeAudio(
       transport_config,
       base::Bind(&AudioSender::OnReceivedCastFeedback,
                  weak_factory_.GetWeakPtr()),
       base::Bind(&AudioSender::OnMeasuredRoundTripTime,
                  weak_factory_.GetWeakPtr()));
 }
 
 AudioSender::~AudioSender() {}
 
 void AudioSender::InsertAudio(scoped_ptr<AudioBus> audio_bus,
                               const base::TimeTicks& recorded_time) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
-  if (cast_initialization_status_ != STATUS_AUDIO_INITIALIZED) {
+
+  if (!audio_encoder_) {
     NOTREACHED();
     return;
   }
-  DCHECK(audio_encoder_.get()) << "Invalid internal state";
 
   const base::TimeDelta next_frame_duration =
       RtpDeltaToTimeDelta(audio_bus->frames(), rtp_timebase());
   if (ShouldDropNextFrame(next_frame_duration))
     return;
 
   samples_in_encoder_ += audio_bus->frames();
 
   audio_encoder_->InsertAudio(audio_bus.Pass(), recorded_time);
 }
@@ skipping 20 matching lines @@
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
 
   samples_in_encoder_ -= audio_encoder_->GetSamplesPerFrame() + samples_skipped;
   DCHECK_GE(samples_in_encoder_, 0);
 
   SendEncodedFrame(encoder_bitrate, encoded_frame.Pass());
 }
 
 }  // namespace cast
 }  // namespace media