Replace RTC_DCHECK(false) with RTC_NOTREACHED().

webrtc/p2p/base/p2ptransportchannel.cc

Index: webrtc/p2p/base/p2ptransportchannel.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index 3fdaf0bad8e30427b2650b5b7d103aa61d4425a1..3fef947109eb93e17481479242289b0407c80c1a 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -1420,7 +1420,7 @@ void P2PTransportChannel::UpdateState() {
         RTC_DCHECK(state == STATE_CONNECTING || state == STATE_COMPLETED);
         break;
       default:
-        RTC_DCHECK(false);
+        RTC_NOTREACHED();
         break;
     }
     state_ = state;
@@ -1759,7 +1759,7 @@ bool P2PTransportChannel::GetUseCandidateAttr(Connection* conn,
       return selected || better_than_selected;
     }
     default:
-      RTC_DCHECK(false);
+      RTC_NOTREACHED();
       return false;
   }
 }