Fix the flaky WebRtcSessionTest.TestRtxRemovedByCreateAnswer.

webrtc/api/webrtcsession_unittest.cc

Index: webrtc/api/webrtcsession_unittest.cc
diff --git a/webrtc/api/webrtcsession_unittest.cc b/webrtc/api/webrtcsession_unittest.cc
index feb1518db0114b6591ec483b5ffecb152dba9b7d..45c7424410b4270fdbff26b7ab3532ea9d748af3 100644
--- a/webrtc/api/webrtcsession_unittest.cc
+++ b/webrtc/api/webrtcsession_unittest.cc
@@ -4284,15 +4284,9 @@ TEST_P(WebRtcSessionTest, TestRenegotiateNewMediaWithCandidatesSeparated) {
   SetLocalDescriptionWithoutError(answer);
 }
 
-// Flaky on Win and Mac only. See webrtc:4943
-#if defined(WEBRTC_WIN) || defined(WEBRTC_MAC)
-#define MAYBE_TestRtxRemovedByCreateAnswer DISABLED_TestRtxRemovedByCreateAnswer
-#else
-#define MAYBE_TestRtxRemovedByCreateAnswer TestRtxRemovedByCreateAnswer
-#endif
 // Tests that RTX codec is removed from the answer when it isn't supported
 // by local side.
-TEST_F(WebRtcSessionTest, MAYBE_TestRtxRemovedByCreateAnswer) {
+TEST_F(WebRtcSessionTest, TestRtxRemovedByCreateAnswer) {
   Init();
   SendAudioVideoStream1();
   std::string offer_sdp(kSdpWithRtx);
@@ -4306,11 +4300,19 @@ TEST_F(WebRtcSessionTest, MAYBE_TestRtxRemovedByCreateAnswer) {
   SetRemoteDescriptionWithoutError(offer);
 
   SessionDescriptionInterface* answer = CreateAnswer();
-  std::string answer_sdp;
-  answer->ToString(&answer_sdp);
-  // Answer SDP removes the unsupported RTX codec.
-  EXPECT_TRUE(answer_sdp.find("rtx") == std::string::npos);
   SetLocalDescriptionWithoutError(answer);
+
+  for (const auto& content : answer->description()->contents()) {
+    if (static_cast<cricket::MediaContentDescription*>(content.description)
+            ->type() == cricket::MEDIA_TYPE_VIDEO) {
+      const auto* mdesc =
+          static_cast<cricket::VideoContentDescription*>(content.description);
+      for (auto iter = mdesc->codecs().begin(); iter != mdesc->codecs().end();

[Taylor Brandstetter, 2016/04/23 00:05:14]

nit: We can use C++11 range-based for loops in new code. So:

for (const VideoCodec& codec : mdesc->codecs()) {
...
} 

[Zhi Huang, 2016/04/23 00:51:57]

Done.

+           iter++) {
+        EXPECT_TRUE(iter->ToString().find("rtx") == std::string::npos);

[Taylor Brandstetter, 2016/04/23 00:05:14]

I think you can just check that the codec's name is not "rtx". So:

EXPECT_NE("rtx", codec.name);

[Zhi Huang, 2016/04/23 00:51:57]

Acknowledged.

+      }
+    }
+  }
 }
 
 // This verifies that the voice channel after bundle has both options from video