Prevent default actions for JS-generated mouse events other than click

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index a74976298f34febfd53070af0f9f9101479e22c4..9b6068ef9943ad220e383457f74814f56b3abbc1 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -2060,8 +2060,10 @@ void Node::dispatchScopedEventDispatchMediator(PassRefPtrWillBeRawPtr<EventDispa
 
 bool Node::dispatchEvent(PassRefPtrWillBeRawPtr<Event> event)
 {
-    if (event->isMouseEvent())
-        return EventDispatcher::dispatchEvent(*this, MouseEventDispatchMediator::create(static_pointer_cast<MouseEvent>(event), MouseEventDispatchMediator::SyntheticMouseEvent));
+    if (event->isMouseEvent()) {
+        toMouseEvent(*event).setFromScript();
+        return EventDispatcher::dispatchEvent(*this, MouseEventDispatchMediator::create(static_pointer_cast<MouseEvent>(event)));
+    }
     if (event->isTouchEvent())
         return dispatchTouchEvent(static_pointer_cast<TouchEvent>(event));
     return EventDispatcher::dispatchEvent(*this, EventDispatchMediator::create(event));