Fixing some case-sensitive codec name comparisons.

As specified in RFC 4288, Section 4.2, and RFC 4855, Section 3, these
names should be case-insensitive. They already were being treated as
case-insensitive in some other places.

This bug was resulting in either a crash or no decoded video, depending
on the platform.

BUG=webrtc:6439, webrtc:7027

Review-Url: https://codereview.webrtc.org/2782273002
Cr-Commit-Position: refs/heads/master@{#17515}

webrtc/pc/peerconnection_integrationtest.cc

@@ -245,7 +245,7 @@ class PeerConnectionWrapper : public webrtc::PeerConnectionObserver,
     received_sdp_munger_ = munger;
   }
 
-  // Siimlar to the above, but this is run on SDP immediately after it's
+  // Similar to the above, but this is run on SDP immediately after it's
   // generated.
   void SetGeneratedSdpMunger(
       std::function<void(cricket::SessionDescription*)> munger) {
@@ -2701,6 +2701,60 @@ TEST_F(PeerConnectionIntegrationTest, EndToEndConnectionTimeWithTurnTurnPair) {
   delete SetCalleePcWrapperAndReturnCurrent(nullptr);
 }
 
+// Test that audio and video flow end-to-end when codec names don't use the
+// expected casing, given that they're supposed to be case insensitive. To test
+// this, all but one codec is removed from each media description, and its
+// casing is changed.
+//
+// In the past, this has regressed and caused crashes/black video, due to the
+// fact that code at some layers was doing case-insensitive comparisons and
+// code at other layers was not.
+TEST_F(PeerConnectionIntegrationTest, CodecNamesAreCaseInsensitive) {
+  ASSERT_TRUE(CreatePeerConnectionWrappers());
+  ConnectFakeSignaling();
+  caller()->AddAudioVideoMediaStream();
+  callee()->AddAudioVideoMediaStream();
+
+  // Remove all but one audio/video codec (opus and VP8), and change the
+  // casing of the caller's generated offer.
+  caller()->SetGeneratedSdpMunger([](cricket::SessionDescription* description) {
+    cricket::AudioContentDescription* audio =
+        GetFirstAudioContentDescription(description);
+    ASSERT_NE(nullptr, audio);
+    auto audio_codecs = audio->codecs();
+    audio_codecs.erase(std::remove_if(audio_codecs.begin(), audio_codecs.end(),
+                                      [](const cricket::AudioCodec& codec) {
+                                        return codec.name != "opus";
+                                      }),
+                       audio_codecs.end());
+    ASSERT_EQ(1u, audio_codecs.size());
+    audio_codecs[0].name = "OpUs";
+    audio->set_codecs(audio_codecs);
+
+    cricket::VideoContentDescription* video =
+        GetFirstVideoContentDescription(description);
+    ASSERT_NE(nullptr, video);
+    auto video_codecs = video->codecs();
+    video_codecs.erase(std::remove_if(video_codecs.begin(), video_codecs.end(),
+                                      [](const cricket::VideoCodec& codec) {
+                                        return codec.name != "VP8";
+                                      }),
+                       video_codecs.end());
+    ASSERT_EQ(1u, video_codecs.size());
+    video_codecs[0].name = "vP8";
+    video->set_codecs(video_codecs);
+  });
+
+  caller()->CreateAndSetAndSignalOffer();
+  ASSERT_TRUE_WAIT(SignalingStateStable(), kDefaultTimeout);
+
+  // Verify frames are still received end-to-end.
+  ExpectNewFramesReceivedWithWait(
+      kDefaultExpectedAudioFrameCount, kDefaultExpectedVideoFrameCount,
+      kDefaultExpectedAudioFrameCount, kDefaultExpectedVideoFrameCount,
+      kMaxWaitForFramesMs);
+}
+
 }  // namespace
 
 #endif  // if !defined(THREAD_SANITIZER)

webrtc/video/send_statistics_proxy.cc

@@ -18,6 +18,7 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/trace_event.h"
+#include "webrtc/common_types.h"
 #include "webrtc/modules/video_coding/include/video_codec_interface.h"
 #include "webrtc/system_wrappers/include/metrics.h"
 
@@ -50,15 +51,21 @@ const char* GetUmaPrefix(VideoEncoderConfig::ContentType content_type) {
 
 HistogramCodecType PayloadNameToHistogramCodecType(
     const std::string& payload_name) {
-  if (payload_name == "VP8") {
-    return kVideoVp8;
-  } else if (payload_name == "VP9") {
-    return kVideoVp9;
-  } else if (payload_name == "H264") {
-    return kVideoH264;
-  } else {
+  rtc::Optional<VideoCodecType> codecType =
+      PayloadNameToCodecType(payload_name);
+  if (!codecType) {
     return kVideoUnknown;
   }
+  switch (*codecType) {
+    case kVideoCodecVP8:
+      return kVideoVp8;
+    case kVideoCodecVP9:
+      return kVideoVp9;
+    case kVideoCodecH264:
+      return kVideoH264;
+    default:
+      return kVideoUnknown;
+  }
 }
 
 void UpdateCodecTypeHistogram(const std::string& payload_name) {

webrtc/video/video_receive_stream.cc

@@ -21,6 +21,7 @@
 #include "webrtc/base/logging.h"
 #include "webrtc/base/optional.h"
 #include "webrtc/base/trace_event.h"
+#include "webrtc/common_types.h"
 #include "webrtc/common_video/h264/profile_level_id.h"
 #include "webrtc/common_video/libyuv/include/webrtc_libyuv.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_receiver.h"
@@ -142,15 +143,8 @@ VideoCodec CreateDecoderVideoCodec(const VideoReceiveStream::Decoder& decoder) {
 
   codec.plType = decoder.payload_type;
   strncpy(codec.plName, decoder.payload_name.c_str(), sizeof(codec.plName));
-  if (decoder.payload_name == "VP8") {
-    codec.codecType = kVideoCodecVP8;
-  } else if (decoder.payload_name == "VP9") {
-    codec.codecType = kVideoCodecVP9;
-  } else if (decoder.payload_name == "H264") {
-    codec.codecType = kVideoCodecH264;
-  } else {
-    codec.codecType = kVideoCodecGeneric;
-  }
+  codec.codecType =
+      PayloadNameToCodecType(decoder.payload_name).value_or(kVideoCodecGeneric);
 
   if (codec.codecType == kVideoCodecVP8) {
     *(codec.VP8()) = VideoEncoder::GetDefaultVp8Settings();

webrtc/video/video_send_stream.cc

@@ -263,9 +263,14 @@ std::string VideoSendStream::StreamStats::ToString() const {
 namespace {
 
 bool PayloadTypeSupportsSkippingFecPackets(const std::string& payload_name) {
-  if (payload_name == "VP8" || payload_name == "VP9")
+  rtc::Optional<VideoCodecType> codecType =
+      PayloadNameToCodecType(payload_name);
+  if (codecType &&
+      (*codecType == kVideoCodecVP8 || *codecType == kVideoCodecVP9)) {
     return true;
-  RTC_DCHECK(payload_name == "H264" || payload_name == "FAKE")
+  }
+  RTC_DCHECK((codecType && *codecType == kVideoCodecH264) ||
+             payload_name == "FAKE")
       << "unknown payload_name " << payload_name;
   return false;
 }