Return false if PeerConnection::GetStats() is called on invalid tracks

webrtc/api/peerconnectioninterface_unittest.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 1559 matching lines @@
 TEST_F(PeerConnectionInterfaceTest, GetStatsForVideoTrack) {
   InitiateCall();
   ASSERT_LT(0u, pc_->remote_streams()->count());
   ASSERT_LT(0u, pc_->remote_streams()->at(0)->GetVideoTracks().size());
   rtc::scoped_refptr<MediaStreamTrackInterface> remote_video =
       pc_->remote_streams()->at(0)->GetVideoTracks()[0];
   EXPECT_TRUE(DoGetStats(remote_video));
 }
 
 // Test that we don't get statistics for an invalid track.
-// TODO(tommi): Fix this test.  DoGetStats will return true
-// for the unknown track (since GetStats is async), but no
-// data is returned for the track.
-TEST_F(PeerConnectionInterfaceTest, DISABLED_GetStatsForInvalidTrack) {
+TEST_F(PeerConnectionInterfaceTest, GetStatsForInvalidTrack) {
   InitiateCall();
   rtc::scoped_refptr<AudioTrackInterface> unknown_audio_track(
       pc_factory_->CreateAudioTrack("unknown track", NULL));
   EXPECT_FALSE(DoGetStats(unknown_audio_track));
 }
 
 // This test setup two RTP data channels in loop back.
 TEST_F(PeerConnectionInterfaceTest, TestDataChannel) {
   FakeConstraints constraints;
   constraints.SetAllowRtpDataChannels();
@@ skipping 1298 matching lines @@
   FakeConstraints updated_answer_c;
   answer_c.SetMandatoryReceiveAudio(false);
   answer_c.SetMandatoryReceiveVideo(false);
 
   cricket::MediaSessionOptions updated_answer_options;
   EXPECT_TRUE(
       ParseConstraintsForAnswer(&updated_answer_c, &updated_answer_options));
   EXPECT_TRUE(updated_answer_options.has_audio());
   EXPECT_TRUE(updated_answer_options.has_video());
 }