Bug 719320 part.8-10 Remove the code handling legacy mouse events in layout r=smaug

layout/base/nsPresShell.cpp

@@ -5659,10 +5659,8 @@ PresShell::HandleEvent(nsIFrame        *aFrame,
   NS_TIME_FUNCTION_MIN(1.0);
 
   nsIContent* capturingContent =
-    NS_IS_MOUSE_EVENT(aEvent) ||
-      aEvent->eventStructType == NS_MOUSE_SCROLL_EVENT ||
-      aEvent->eventStructType == NS_WHEEL_EVENT ?
-        GetCapturingContent() : nullptr;
+    NS_IS_MOUSE_EVENT(aEvent) || aEvent->eventStructType == NS_WHEEL_EVENT ?
+      GetCapturingContent() : nullptr;
 
   nsCOMPtr<nsIDocument> retargetEventDoc;
   if (!aDontRetargetEvents) {

layout/generic/nsObjectFrame.cpp

@@ -2105,7 +2105,8 @@ nsObjectFrame::HandleEvent(nsPresContext* aPresContext,
 
 #ifdef XP_MACOSX
   // we want to process some native mouse events in the cocoa event model
-  if ((anEvent->message == NS_MOUSE_ENTER || anEvent->message == NS_MOUSE_SCROLL) &&
+  if ((anEvent->message == NS_MOUSE_ENTER ||
+       anEvent->message == NS_WHEEL_WHEEL) &&
       mInstanceOwner->GetEventModel() == NPEventModelCocoa) {
     *anEventStatus = mInstanceOwner->ProcessEvent(*anEvent);
     return rv;