Revert of Remove AudioTrackRenderer

talk/media/webrtc/webrtcvoiceengine.cc

Index: talk/media/webrtc/webrtcvoiceengine.cc
diff --git a/talk/media/webrtc/webrtcvoiceengine.cc b/talk/media/webrtc/webrtcvoiceengine.cc
index db22b41fc0d476639bd8629bdb1d6da53259031c..54fac221d8fb7d6d829f606e8ab5f9897dc2469a 100644
--- a/talk/media/webrtc/webrtcvoiceengine.cc
+++ b/talk/media/webrtc/webrtcvoiceengine.cc
@@ -1305,6 +1305,10 @@
       RTC_DCHECK(renderer_ == renderer);
       return;
     }
+
+    // TODO(xians): Remove AddChannel() call after Chrome turns on APM
+    // in getUserMedia by default.
+    renderer->AddChannel(channel_);
     renderer->SetSink(this);
     renderer_ = renderer;
   }
@@ -1314,10 +1318,12 @@
   // This method is called on the libjingle worker thread.
   void Stop() {
     rtc::CritScope lock(&lock_);
-    if (renderer_ != NULL) {
-      renderer_->SetSink(NULL);
-      renderer_ = NULL;
-    }
+    if (renderer_ == NULL)
+      return;
+
+    renderer_->RemoveChannel(channel_);
+    renderer_->SetSink(NULL);
+    renderer_ = NULL;
   }
 
   // AudioRenderer::Sink implementation.