Revert of Stop using hardcoded payload types for video codecs

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 628eb0cc91038ce636c1ba52843d509fd1a62b5a..6ff8c0f658aec862c3c84fb07e4d48d2281d9299 100644
--- a/webrtc/media/engine/payload_type_mapper_unittest.cc
+++ b/webrtc/media/engine/payload_type_mapper_unittest.cc
@@ -60,8 +60,28 @@
 }
 
 TEST_F(PayloadTypeMapperTest, WebRTCPayloadTypes) {
-  // Tests that the payload mapper knows about the audio and data formats we've
-  // been using in WebRTC, with their hard coded values.
+  // Tests that the payload mapper knows about the formats we've been using in
+  // WebRTC, with their hard coded values.
+  auto video_mapping = [this] (const char *name) {
+    return FindMapping({name, kVideoCodecClockrate, 0});
+  };
+  EXPECT_EQ(kDefaultVp8PlType,  video_mapping(kVp8CodecName));
+  EXPECT_EQ(kDefaultVp9PlType,  video_mapping(kVp9CodecName));
+  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,
+        {{ kCodecParamAssociatedPayloadType, std::to_string(payload_type)}}});
+  };
+  EXPECT_EQ(kDefaultRtxVp8PlType,  rtx_mapping(kDefaultVp8PlType));
+  EXPECT_EQ(kDefaultRtxVp9PlType,  rtx_mapping(kDefaultVp9PlType));
+  EXPECT_EQ(kDefaultRtxH264ConstrainedBaselinePlType,
+            rtx_mapping(kDefaultH264PlType));
+  EXPECT_EQ(kDefaultRtxRedPlType,  rtx_mapping(kDefaultRedPlType));
+
   auto data_mapping = [this] (const char *name) {
     return FindMapping({name, 0, 0});
   };