Early initialize recording on the ADM from WebRtcVoiceMediaChannel.

webrtc/media/engine/webrtcvoiceengine.cc

Index: webrtc/media/engine/webrtcvoiceengine.cc
diff --git a/webrtc/media/engine/webrtcvoiceengine.cc b/webrtc/media/engine/webrtcvoiceengine.cc
index 7ae7062f63fda5a0d2c0d2284b8271836e1f8f5b..e1cd77a3ce718ef0d928171025936d652d2497e7 100644
--- a/webrtc/media/engine/webrtcvoiceengine.cc
+++ b/webrtc/media/engine/webrtcvoiceengine.cc
@@ -1111,6 +1111,12 @@ int WebRtcVoiceEngine::CreateVoEChannel() {
   return voe_wrapper_->base()->CreateChannel(voe_config_);
 }
 
+webrtc::AudioDeviceModule* WebRtcVoiceEngine::adm() {
+  RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
+  RTC_DCHECK(adm_);
+  return adm_;
+}
+
 class WebRtcVoiceMediaChannel::WebRtcAudioSendStream
     : public AudioSource::Sink {
  public:
@@ -1833,9 +1839,11 @@ void WebRtcVoiceMediaChannel::SetSend(bool send) {
     return;
   }
 
-  // Apply channel specific options when channel is enabled for sending.
+  // Apply channel specific options, and initialize ADM for recording, when
+  // channel is enabled for sending.
   if (send) {
     engine()->ApplyOptions(options_);
+    SetupRecording();
   }
 
   // Change the settings on each send channel.
@@ -1941,6 +1949,10 @@ bool WebRtcVoiceMediaChannel::AddSendStream(const StreamParams& sp) {
     }
   }
 
+  // Initialize ADM for recording.
+  if (send_) {
+    SetupRecording();
+  }
   send_streams_[ssrc]->SetSend(send_);
   return true;
 }
@@ -2522,6 +2534,18 @@ bool WebRtcVoiceMediaChannel::SetPlayout(int channel, bool playout) {
   }
   return true;
 }
+
+void WebRtcVoiceMediaChannel::SetupRecording() {

[Taylor Brandstetter, 2016/03/29 01:05:37]

Maybe add a comment explaining that this is done as a performance optimization,
in case people wonder later why InitRecording is called in two places.

[the sun, 2016/03/31 10:49:47]

Done.

+  if (engine()->adm()->InitRecording() != 0) {
+    LOG(LS_WARNING) << "Foo";
+    return;
+  }
+  if (!send_streams_.empty()) {
+    if (engine()->adm()->StartRecording() != 0) {

[Taylor Brandstetter, 2016/03/29 01:05:37]

It's really only "InitRecording" that was slow on Android. I'm not sure about
the side-effects of calling "StartRecording" early on various platforms, so
maybe we should leave that out for now?

[the sun, 2016/03/31 10:49:47]

Note that StartRecording() is only called once we have a stream to send &&
sending is enabled. Added a comment.

[Taylor Brandstetter, 2016/03/31 18:11:25]

But after my recent change, a stream won't call "Start" until it's enabled for
sending *and* has a source (look in "UpdateSendState"). If an application does
an initial offer/answer just to get ICE connected/etc., sending may be enabled
here even when the application isn't ready to start sending media.

[the sun, 2016/04/01 09:07:46]

Ah, thanks for explaining. I decided to leave the old call to
VoEBase::StartSend() in AudioSendStream and only make the speculative call to
InitRecording() from WVoMC::SetSend().

+      LOG(LS_WARNING) << "Bar";
+    }
+  }
+}
 }  // namespace cricket
 
 #endif  // HAVE_WEBRTC_VOICE