MediaStream audio sourcing: Bypass audio processing for non-WebRTC cases.

content/renderer/media/user_media_client_impl.cc

Index: content/renderer/media/user_media_client_impl.cc
diff --git a/content/renderer/media/user_media_client_impl.cc b/content/renderer/media/user_media_client_impl.cc
index 15e096b6469d9b1bc061d68be7d41c99bb18666c..e6e40d377dd3fd9754bfd9948869228d486580f7 100644
--- a/content/renderer/media/user_media_client_impl.cc
+++ b/content/renderer/media/user_media_client_impl.cc
@@ -598,14 +598,22 @@ void UserMediaClientImpl::InitializeSourceObject(
                        weak_factory_.GetWeakPtr())));
   } else {
     DCHECK_EQ(blink::WebMediaStreamSource::TypeAudio, type);
-    MediaStreamAudioSource* audio_source(
-        new MediaStreamAudioSource(
-            RenderFrameObserver::routing_id(),
-            device,
-            base::Bind(&UserMediaClientImpl::OnLocalSourceStopped,
-                       weak_factory_.GetWeakPtr()),
-            dependency_factory_));
-    webkit_source->setExtraData(audio_source);
+    MediaStreamAudioSource* audio_source;
+    // When no RenderFrame was provided, create a "null"
+    // MediaStreamAudioSource.  This should only happen for non-browser unit
+    // tests (e.g., user_media_client_impl_unittest.cc).
+    if (RenderFrameObserver::render_frame()) {
+      audio_source =
+          new MediaStreamAudioSource(RenderFrameObserver::routing_id(), device);
+    } else {
+      audio_source = new MediaStreamAudioSource();
+      audio_source->SetDeviceInfo(device);
+    }
+    audio_source->SetStopCallback(
+        base::Bind(&UserMediaClientImpl::OnLocalSourceStopped,
+                   weak_factory_.GetWeakPtr()));
+    audio_source->set_dependency_factory(dependency_factory_);
+    webkit_source->setExtraData(audio_source);  // Takes ownership.
   }
   local_sources_.push_back(*webkit_source);
 }
@@ -1055,10 +1063,10 @@ void UserMediaClientImpl::UserMediaRequestInfo::StartAudioTrack(
 
   sources_.push_back(track.source());
   sources_waiting_for_callback_.push_back(native_source);
-  native_source->AddTrack(
-      track, constraints, base::Bind(
-          &UserMediaClientImpl::UserMediaRequestInfo::OnTrackStarted,
-          AsWeakPtr()));
+  if (native_source->ConnectToTrack(track, constraints))
+    OnTrackStarted(native_source, MEDIA_DEVICE_OK, "");
+  else
+    OnTrackStarted(native_source, MEDIA_DEVICE_TRACK_START_FAILURE, "");
 }
 
 blink::WebMediaStreamTrack