Revert of Adding "first packet received" notification to PeerConnectionObserver. (patchset #5 id:80001 of https://codereview.webrtc.org/1581693006/ )

Reason for revert:
onFirstMediaPacketReceived() breaks bot.

Original issue's description:
> Adding "first packet received" notification to PeerConnectionObserver.
>
> R=glaznev@webrtc.org, pthatcher@webrtc.org, tkchin@webrtc.org
>
> Committed: https://crrev.com/42265a8cc3b3f3db4aa2c29005aed2fb4393adef
> Cr-Commit-Position: refs/heads/master@{#11401}
>
> Committed: https://crrev.com/08a6eab75e13613183509d91d3892c1db57f6fc5
> Cr-Commit-Position: refs/heads/master@{#11404}

TBR=pthatcher@webrtc.org,tkchin@webrtc.org,glaznev@webrtc.org,deadbeef@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.webrtc.org/1647483004

Cr-Commit-Position: refs/heads/master@{#11415}

talk/app/webrtc/java/jni/peerconnection_jni.cc

@@ -374,14 +374,6 @@ class PCOJava : public PeerConnectionObserver {
     CHECK_EXCEPTION(jni()) << "error during CallVoidMethod";
   }
 
-  void OnFirstMediaPacketReceived() override {
-    ScopedLocalRefFrame local_ref_frame(jni());
-    jmethodID m = GetMethodID(jni(), *j_observer_class_,
-                              "onFirstMediaPacketReceived", "()V");
-    jni()->CallVoidMethod(*j_observer_global_, m);
-    CHECK_EXCEPTION(jni()) << "error during CallVoidMethod";
-  }
-
   void SetConstraints(ConstraintsWrapper* constraints) {
     RTC_CHECK(!constraints_.get()) << "constraints already set!";
     constraints_.reset(constraints);

talk/app/webrtc/java/src/org/webrtc/PeerConnection.java

@@ -86,9 +86,6 @@ public class PeerConnection {
 
     /** Triggered when renegotiation is necessary. */
     public void onRenegotiationNeeded();
-
-    /** Called when the first RTP packet is received. */
-    public void onFirstMediaPacketReceived();
   }
 
   /** Java version of PeerConnectionInterface.IceServer. */

talk/app/webrtc/java/testcommon/src/org/webrtc/PeerConnectionTest.java

@@ -289,9 +289,6 @@ public class PeerConnectionTest {
       ++expectedStatsCallbacks;
     }
 
-    @Override
-    public synchronized void onFirstMediaPacketReceived() {}
-
     public synchronized LinkedList<StatsReport[]> takeStatsReports() {
       LinkedList<StatsReport[]> got = gotStatsReports;
       gotStatsReports = new LinkedList<StatsReport[]>();

talk/app/webrtc/objc/RTCPeerConnectionObserver.h

@@ -68,9 +68,6 @@ class RTCPeerConnectionObserver : public PeerConnectionObserver {
   // New Ice candidate have been found.
   void OnIceCandidate(const IceCandidateInterface* candidate) override;
 
-  // Called when the first RTP packet is received.
-  void OnFirstMediaPacketReceived() override;
-
  private:
   __weak RTCPeerConnection* _peerConnection;
 };

talk/app/webrtc/objc/RTCPeerConnectionObserver.mm

@@ -105,9 +105,4 @@ void RTCPeerConnectionObserver::OnIceCandidate(
                            gotICECandidate:iceCandidate];
 }
 
-void RTCPeerConnectionObserver::OnFirstMediaPacketReceived() {
-  id<RTCPeerConnectionDelegate> delegate = _peerConnection.delegate;
-  [delegate peerConnectionOnFirstMediaPacketReceived:_peerConnection];
-}
-
 }  // namespace webrtc

talk/app/webrtc/objc/public/RTCPeerConnectionDelegate.h

@@ -69,8 +69,4 @@
 - (void)peerConnection:(RTCPeerConnection*)peerConnection
     didOpenDataChannel:(RTCDataChannel*)dataChannel;
 
-// Called when the first RTP packet is received.
-- (void)peerConnectionOnFirstMediaPacketReceived:
-    (RTCPeerConnection *)peerConnection;
-
 @end

talk/app/webrtc/objctests/RTCPeerConnectionSyncObserver.m

@@ -233,10 +233,6 @@
            @"Unexpected state");
 }
 
-- (void)peerConnectionOnFirstMediaPacketReceived:
-    (RTCPeerConnection*)peerConnection {
-}
-
 #pragma mark - RTCDataChannelDelegate
 
 - (void)channelDidChangeState:(RTCDataChannel*)channel {

talk/app/webrtc/peerconnection.cc

@@ -663,8 +663,6 @@ bool PeerConnection::Initialize(
       this, &PeerConnection::OnDataChannelDestroyed);
   session_->SignalDataChannelOpenMessage.connect(
       this, &PeerConnection::OnDataChannelOpenMessage);
-  session_->SignalFirstMediaPacketReceived.connect(
-      this, &PeerConnection::OnFirstMediaPacketReceived);
   return true;
 }
 
@@ -2031,11 +2029,6 @@ void PeerConnection::OnDataChannelOpenMessage(
       DataChannelProxy::Create(signaling_thread(), channel));
 }
 
-void PeerConnection::OnFirstMediaPacketReceived() {
-  RTC_DCHECK(signaling_thread()->IsCurrent());
-  observer_->OnFirstMediaPacketReceived();
-}
-
 RtpSenderInterface* PeerConnection::FindSenderById(const std::string& id) {
   auto it =
       std::find_if(senders_.begin(), senders_.end(),

talk/app/webrtc/peerconnection.h

@@ -326,7 +326,6 @@ class PeerConnection : public PeerConnectionInterface,
   // webrtc::DataChannel should be opened.
   void OnDataChannelOpenMessage(const std::string& label,
                                 const InternalDataChannelInit& config);
-  void OnFirstMediaPacketReceived();
 
   RtpSenderInterface* FindSenderById(const std::string& id);
 

talk/app/webrtc/peerconnection_unittest.cc

@@ -251,7 +251,6 @@ class PeerConnectionTestClient : public webrtc::PeerConnectionObserver,
     signaling_message_receiver_->ReceiveIceMessage(
         candidate->sdp_mid(), candidate->sdp_mline_index(), ice_sdp);
   }
-  void OnFirstMediaPacketReceived() override { received_media_packet_ = true; }
 
   // MediaStreamInterface callback
   void OnChanged() override {
@@ -387,8 +386,6 @@ class PeerConnectionTestClient : public webrtc::PeerConnectionObserver,
     return true;
   }
 
-  bool received_media_packet() const { return received_media_packet_; }
-
   void OnIceComplete() override { LOG(INFO) << id_ << "OnIceComplete"; }
 
   void OnDataChannel(DataChannelInterface* data_channel) override {
@@ -927,10 +924,6 @@ class PeerConnectionTestClient : public webrtc::PeerConnectionObserver,
 
   rtc::scoped_refptr<DataChannelInterface> data_channel_;
   rtc::scoped_ptr<MockDataChannelObserver> data_observer_;
-
-  // "true" if the PeerConnection indicated that a packet was received,
-  // through PeerConnectionObserverInterface.
-  bool received_media_packet_ = false;
 };
 
 class P2PTestConductor : public testing::Test {
@@ -1111,12 +1104,6 @@ class P2PTestConductor : public testing::Test {
 
     EXPECT_TRUE_WAIT(FramesNotPending(audio_frame_count, video_frame_count),
                      kMaxWaitForFramesMs);
-    if (audio_frame_count != -1 || video_frame_count != -1) {
-      EXPECT_TRUE_WAIT(initiating_client_->received_media_packet(),
-                       kMaxWaitForFramesMs);
-      EXPECT_TRUE_WAIT(receiving_client_->received_media_packet(),
-                       kMaxWaitForFramesMs);
-    }
   }
 
   void SetupAndVerifyDtlsCall() {

talk/app/webrtc/peerconnectioninterface.h

@@ -501,9 +501,6 @@ class PeerConnectionObserver {
   // Called when the ICE connection receiving status changes.
   virtual void OnIceConnectionReceivingChange(bool receiving) {}
 
-  // Called when the first RTP packet is received.
-  virtual void OnFirstMediaPacketReceived() {}
-
  protected:
   // Dtor protected as objects shouldn't be deleted via this interface.
   ~PeerConnectionObserver() {}

talk/app/webrtc/webrtcsession.cc

@@ -1844,8 +1844,6 @@ bool WebRtcSession::CreateVoiceChannel(const cricket::ContentInfo* content) {
 
   voice_channel_->SignalDtlsSetupFailure.connect(
       this, &WebRtcSession::OnDtlsSetupFailure);
-  voice_channel_->SignalFirstPacketReceived.connect(
-      this, &WebRtcSession::OnChannelFirstPacketReceived);
 
   SignalVoiceChannelCreated();
   voice_channel_->transport_channel()->SignalSentPacket.connect(
@@ -1863,8 +1861,6 @@ bool WebRtcSession::CreateVideoChannel(const cricket::ContentInfo* content) {
 
   video_channel_->SignalDtlsSetupFailure.connect(
       this, &WebRtcSession::OnDtlsSetupFailure);
-  video_channel_->SignalFirstPacketReceived.connect(
-      this, &WebRtcSession::OnChannelFirstPacketReceived);
 
   SignalVideoChannelCreated();
   video_channel_->transport_channel()->SignalSentPacket.connect(
@@ -1899,14 +1895,6 @@ void WebRtcSession::OnDtlsSetupFailure(cricket::BaseChannel*, bool rtcp) {
            rtcp ? kDtlsSetupFailureRtcp : kDtlsSetupFailureRtp);
 }
 
-void WebRtcSession::OnChannelFirstPacketReceived(cricket::BaseChannel*) {
-  ASSERT(signaling_thread()->IsCurrent());
-  if (!has_received_media_packet_) {
-    has_received_media_packet_ = true;
-    SignalFirstMediaPacketReceived();
-  }
-}
-
 void WebRtcSession::OnDataChannelMessageReceived(
     cricket::DataChannel* channel,
     const cricket::ReceiveDataParams& params,

talk/app/webrtc/webrtcsession.h

@@ -309,7 +309,6 @@ class WebRtcSession : public AudioProviderInterface,
   void OnCertificateReady(
       const rtc::scoped_refptr<rtc::RTCCertificate>& certificate);
   void OnDtlsSetupFailure(cricket::BaseChannel*, bool rtcp);
-  void OnChannelFirstPacketReceived(cricket::BaseChannel*);
 
   // For unit test.
   bool waiting_for_certificate_for_testing() const;
@@ -336,9 +335,6 @@ class WebRtcSession : public AudioProviderInterface,
   sigslot::signal2<const std::string&, const InternalDataChannelInit&>
       SignalDataChannelOpenMessage;
 
-  // Called when the first RTP packet is received.
-  sigslot::signal0<> SignalFirstMediaPacketReceived;
-
  private:
   // Indicates the type of SessionDescription in a call to SetLocalDescription
   // and SetRemoteDescription.
@@ -522,8 +518,6 @@ class WebRtcSession : public AudioProviderInterface,
   // Declares the RTCP mux policy for the WebRTCSession.
   PeerConnectionInterface::RtcpMuxPolicy rtcp_mux_policy_;
 
-  bool has_received_media_packet_ = false;
-
   RTC_DISALLOW_COPY_AND_ASSIGN(WebRtcSession);
 };
 }  // namespace webrtc

webrtc/examples/androidapp/src/org/appspot/apprtc/PeerConnectionClient.java

@@ -1000,10 +1000,6 @@ public class PeerConnectionClient {
       // No need to do anything; AppRTC follows a pre-agreed-upon
       // signaling/negotiation protocol.
     }
-
-    @Override
-    public void onFirstMediaPacketReceived() {
-    }
   }
 
   // Implementation detail: handle offer creation/signaling and answer setting,

webrtc/examples/objc/AppRTCDemo/ARDAppClient.m

@@ -384,11 +384,6 @@ static NSInteger const kARDAppClientErrorInvalidRoom = -6;
     didOpenDataChannel:(RTCDataChannel *)dataChannel {
 }
 
-- (void)peerConnectionOnFirstMediaPacketReceived:
-    (RTCPeerConnection *)peerConnection {
-  RTCLog(@"Received first media packet.");
-}
-
 #pragma mark - RTCStatsDelegate
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection