Revert of Use VoiceChannel/VideoChannel directly from RtpSender/RtpReceiver.

webrtc/media/base/fakemediaengine.h

Index: webrtc/media/base/fakemediaengine.h
diff --git a/webrtc/media/base/fakemediaengine.h b/webrtc/media/base/fakemediaengine.h
index a86dcbd924c96674acae756c24841a56dd31c197..3edda5e376245147228a493eb7507b2e6d415ed8 100644
--- a/webrtc/media/base/fakemediaengine.h
+++ b/webrtc/media/base/fakemediaengine.h
@@ -339,11 +339,6 @@
     }
     return true;
   }
-
-  bool HasSource(uint32_t ssrc) const {
-    return local_sinks_.find(ssrc) != local_sinks_.end();
-  }
-
   virtual bool AddRecvStream(const StreamParams& sp) {
     if (!RtpHelper<VoiceMediaChannel>::AddRecvStream(sp))
       return false;
@@ -550,9 +545,6 @@
     }
     return true;
   }
-  bool HasSink(uint32_t ssrc) const {
-    return sinks_.find(ssrc) != sinks_.end() && sinks_.at(ssrc) != nullptr;
-  }
 
   bool SetSend(bool send) override { return set_sending(send); }
   bool SetVideoSend(
@@ -564,17 +556,14 @@
       return false;
     }
     if (enable && options) {
-      if (!SetOptions(*options)) {
-        return false;
-      }
+      return SetOptions(*options);
     }
     sources_[ssrc] = source;
     return true;
   }
 
   bool HasSource(uint32_t ssrc) const {
-    return sources_.find(ssrc) != sources_.end() &&
-           sources_.at(ssrc) != nullptr;
+    return sources_.find(ssrc) != sources_.end();
   }
   bool AddRecvStream(const StreamParams& sp) override {
     if (!RtpHelper<VideoMediaChannel>::AddRecvStream(sp))