fix for bug 18114. Adding simple accessor to PL_WaitForEvent.

xpcom/threads/nsEventQueue.cpp

@@ -224,6 +224,14 @@ nsEventQueueImpl::HandleEvent(PLEvent* aEvent)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsEventQueueImpl::WaitForEvent()
+{
+    PL_WaitForEvent(mEventQueue);
+    CheckForDeactivation();
+    return NS_OK;
+}
+
 NS_IMETHODIMP_(PRInt32) 
 nsEventQueueImpl::GetEventQueueSelectFD() 
 {

xpcom/threads/nsEventQueue.h

@@ -46,6 +46,8 @@ public:
     NS_IMETHOD EventAvailable(PRBool& aResult);
     NS_IMETHOD GetEvent(PLEvent** aResult);
     NS_IMETHOD HandleEvent(PLEvent* aEvent);
+    
+    NS_IMETHOD WaitForEvent();
 
     NS_IMETHOD_(PRInt32) GetEventQueueSelectFD();
 

xpcom/threads/nsIEventQueue.h

@@ -53,6 +53,8 @@ public:
     NS_IMETHOD GetEvent(PLEvent** aResult) = 0;
     NS_IMETHOD HandleEvent(PLEvent* aEvent) = 0;
 
+    NS_IMETHOD WaitForEvent() = 0;
+
     NS_IMETHOD_(PRInt32) GetEventQueueSelectFD() = 0;
 
     NS_IMETHOD Init() = 0;