Reland of TransportController refactoring.

webrtc/p2p/base/portallocator.cc

Index: webrtc/p2p/base/portallocator.cc
diff --git a/webrtc/p2p/base/portallocator.cc b/webrtc/p2p/base/portallocator.cc
index 76455b506e220ad8e3d188b827111ca19e7b12e3..b97ad554d6cf1a05ec5b888cb5dd6524568684f0 100644
--- a/webrtc/p2p/base/portallocator.cc
+++ b/webrtc/p2p/base/portallocator.cc
@@ -8,6 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include "webrtc/base/checks.h"
 #include "webrtc/p2p/base/portallocator.h"
 
 namespace cricket {
@@ -21,8 +22,10 @@
       component_(component),
       flags_(flags),
       generation_(0),
-      username_(ice_ufrag),
-      password_(ice_pwd) {
+      ice_ufrag_(ice_ufrag),
+      ice_pwd_(ice_pwd) {
+  RTC_DCHECK(!ice_ufrag.empty());
+  RTC_DCHECK(!ice_pwd.empty());
 }
 
 PortAllocatorSession* PortAllocator::CreateSession(