Rework dispatchEvent so it is consistent for isTrusted support.

Source/core/events/EventTarget.cpp

Index: Source/core/events/EventTarget.cpp
diff --git a/Source/core/events/EventTarget.cpp b/Source/core/events/EventTarget.cpp
index 09bccffcb2549d8974a6d940984cf832bbca5c7f..d66b217b3b747f170bf2b5daf7aa5e49f2748911 100644
--- a/Source/core/events/EventTarget.cpp
+++ b/Source/core/events/EventTarget.cpp
@@ -182,11 +182,16 @@ bool EventTarget::dispatchEventForBindings(PassRefPtrWillBeRawPtr<Event> event,
     if (!executionContext())
         return false;
 
-    return dispatchEvent(event);
+    return dispatchEventInternal(event);
 }
 
 bool EventTarget::dispatchEvent(PassRefPtrWillBeRawPtr<Event> event)
 {
+    return dispatchEventInternal(event);
+}
+
+bool EventTarget::dispatchEventInternal(PassRefPtrWillBeRawPtr<Event> event)
+{
     event->setTarget(this);
     event->setCurrentTarget(this);
     event->setEventPhase(Event::AT_TARGET);