Removing `preference` field from `cricket::Codec`.

webrtc/media/engine/webrtcvideoengine2_unittest.cc

Index: webrtc/media/engine/webrtcvideoengine2_unittest.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2_unittest.cc b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
index e8800ba66f3cc7e171b008765247b0b624a74365..06e14afda2f7767784949f1c8323067e7c57bc24 100644
--- a/webrtc/media/engine/webrtcvideoengine2_unittest.cc
+++ b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
@@ -2417,6 +2417,27 @@ TEST_F(WebRtcVideoChannel2Test, SetSendCodecsAcceptAllValidPayloadTypes) {
   }
 }
 
+// Test that setting the same codecs but with a different preference for the
+// first codec doesn't result in the stream being recreated.
+// This may happen when a subsequent negotiation includes few codecs, as a
+// result of one of the codecs being rejected.
+TEST_F(WebRtcVideoChannel2Test,
+       SetSendCodecsDifferentPreferenceDoesntRecreateStream) {
+  cricket::VideoSendParameters parameters1;
+  parameters1.codecs.push_back(kVp8Codec);
+  parameters1.codecs.push_back(kVp9Codec);
+  parameters1.codecs[0].preference += 1;
+  EXPECT_TRUE(channel_->SetSendParameters(parameters1));
+
+  AddSendStream();
+  EXPECT_EQ(1, fake_call_->GetNumCreatedSendStreams());
+
+  cricket::VideoSendParameters parameters2;
+  parameters2.codecs.push_back(kVp8Codec);
+  EXPECT_TRUE(channel_->SetSendParameters(parameters2));
+  EXPECT_EQ(1, fake_call_->GetNumCreatedSendStreams());
+}
+
 TEST_F(WebRtcVideoChannel2Test, SetRecvCodecsWithOnlyVp8) {
   cricket::VideoRecvParameters parameters;
   parameters.codecs.push_back(kVp8Codec);