Add new codec for FlexFEC.

webrtc/media/engine/payload_type_mapper_unittest.cc

Index: webrtc/media/engine/payload_type_mapper_unittest.cc
diff --git a/webrtc/media/engine/payload_type_mapper_unittest.cc b/webrtc/media/engine/payload_type_mapper_unittest.cc
index 7f94c6e88c7396b293d0805302c501a4a2c1128a..8e00dbc2b708c8b3435e29f9cd607450017929ed 100644
--- a/webrtc/media/engine/payload_type_mapper_unittest.cc
+++ b/webrtc/media/engine/payload_type_mapper_unittest.cc
@@ -70,6 +70,7 @@ TEST_F(PayloadTypeMapperTest, WebRTCPayloadTypes) {
   EXPECT_EQ(kDefaultH264PlType, video_mapping(kH264CodecName));
   EXPECT_EQ(kDefaultRedPlType,  video_mapping(kRedCodecName));
   EXPECT_EQ(kDefaultUlpfecType, video_mapping(kUlpfecCodecName));
+  EXPECT_EQ(kDefaultFlexfecPlType, video_mapping(kFlexfecCodecName));
 
   auto rtx_mapping = [this] (int payload_type) {
     return FindMapping({kRtxCodecName, kVideoCodecClockrate, 0,