Switch usage of _DEBUG macro to NDEBUG.

webrtc/libjingle/xmpp/xmpplogintask.cc

Index: webrtc/libjingle/xmpp/xmpplogintask.cc
diff --git a/webrtc/libjingle/xmpp/xmpplogintask.cc b/webrtc/libjingle/xmpp/xmpplogintask.cc
index f5745cd979cfacdbdbe176834266b7cf89bbe54e..e39713d463b2ed3f5a4b3239bc36463c93921995 100644
--- a/webrtc/libjingle/xmpp/xmpplogintask.cc
+++ b/webrtc/libjingle/xmpp/xmpplogintask.cc
@@ -25,7 +25,7 @@ using rtc::ConstantLabel;
 
 namespace buzz {
 
-#ifdef _DEBUG
+#if !defined(NDEBUG)
 const ConstantLabel XmppLoginTask::LOGINTASK_STATES[] = {
   KLABEL(LOGINSTATE_INIT),
   KLABEL(LOGINSTATE_STREAMSTART_SENT),
@@ -40,7 +40,7 @@ const ConstantLabel XmppLoginTask::LOGINTASK_STATES[] = {
   KLABEL(LOGINSTATE_DONE),
   LASTLABEL
 };
-#endif  // _DEBUG
+#endif
 XmppLoginTask::XmppLoginTask(XmppEngineImpl * pctx) :
   pctx_(pctx),
   authNeeded_(true),
@@ -84,10 +84,10 @@ XmppLoginTask::Advance() {
 
     const XmlElement * element = NULL;
 
-#if _DEBUG
+#if !defined(NDEBUG)
     LOG(LS_VERBOSE) << "XmppLoginTask::Advance - "
       << rtc::ErrorName(state_, LOGINTASK_STATES);
-#endif  // _DEBUG
+#endif
 
     switch (state_) {