unify "control reaches end of non-void function" style

BUG=webrtc:12008

Change-Id: I1cabe99738b3968af60a305bd9593bd47f7e9b6b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/190480
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32506}
diff --git a/api/media_types.cc b/api/media_types.cc
index c7635b5..4ab80ed 100644
--- a/api/media_types.cc
+++ b/api/media_types.cc
@@ -31,9 +31,7 @@
       RTC_NOTREACHED();
       return "";
   }
-  FATAL();
-  // Not reachable; avoids compile warning.
-  return "";
+  RTC_CHECK(false);
 }
 
 }  // namespace cricket
diff --git a/pc/peer_connection_factory.cc b/pc/peer_connection_factory.cc
index 237c84d..fec600a 100644
--- a/pc/peer_connection_factory.cc
+++ b/pc/peer_connection_factory.cc
@@ -140,8 +140,7 @@
     case cricket::MEDIA_TYPE_UNSUPPORTED:
       return RtpCapabilities();
   }
-  // Not reached; avoids compile warning.
-  FATAL();
+  RTC_CHECK(false);
 }
 
 RtpCapabilities PeerConnectionFactory::GetRtpReceiverCapabilities(
@@ -167,8 +166,7 @@
     case cricket::MEDIA_TYPE_UNSUPPORTED:
       return RtpCapabilities();
   }
-  // Not reached; avoids compile warning.
-  FATAL();
+  RTC_CHECK(false);
 }
 
 rtc::scoped_refptr<AudioSourceInterface>
diff --git a/pc/rtp_parameters_conversion.cc b/pc/rtp_parameters_conversion.cc
index 9c7a337..80e56b8 100644
--- a/pc/rtp_parameters_conversion.cc
+++ b/pc/rtp_parameters_conversion.cc
@@ -76,8 +76,7 @@
       }
       return cricket::FeedbackParam(cricket::kRtcpFbParamTransportCc);
   }
-  // Not reached; avoids compile warning.
-  FATAL();
+  RTC_CHECK(false);
 }
 
 template <typename C>