Changes for threads.

mailnews/db/msgdb/public/nsIMsgDatabase.h

@@ -107,6 +107,7 @@ public:
   NS_IMETHOD ListAllKeys(nsMsgKeyArray &outputKeys) = 0;
 #endif
   NS_IMETHOD EnumerateMessages(nsIEnumerator* *result) = 0;
+  NS_IMETHOD EnumerateThreads(nsIEnumerator* *result) = 0;
 
   // helpers for user command functions like delete, mark read, etc.
 

mailnews/db/msgdb/src/nsMsgDatabase.cpp

@@ -1766,6 +1766,8 @@ NS_IMETHODIMP nsMsgDBThreadEnumerator::Next(void)
 			return rv;
 
         mResultThread = new nsMsgThread(mDB, table);
+		if(mResultThread)
+			NS_ADDREF(mResultThread);
     } while (mFilter && mFilter(mResultThread, mClosure) != NS_OK);
 	return rv;
 }