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

Source/core/events/MouseEvent.h

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 60 matching lines @@
     EventTarget* relatedTarget() const { return m_relatedTarget.get(); }
     void setRelatedTarget(PassRefPtrWillBeRawPtr<EventTarget> relatedTarget) { m_relatedTarget = relatedTarget; }
 
     Node* toElement() const;
     Node* fromElement() const;
 
     DataTransfer* dataTransfer() const { return isDragEvent() ? m_dataTransfer.get() : 0; }
 
     bool fromTouch() const { return m_syntheticEventType == PlatformMouseEvent::FromTouch; }
 
+    bool fromScript() const { return m_syntheticEventType == PlatformMouseEvent::FromScript; }
+    void setFromScript() { m_syntheticEventType = PlatformMouseEvent::FromScript; }
+
     virtual const AtomicString& interfaceName() const override;
 
     virtual bool isMouseEvent() const override;
     virtual bool isDragEvent() const override final;
     virtual int which() const override final;
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     MouseEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtrWillBeRawPtr<AbstractView>,
@@ skipping 22 matching lines @@
     virtual ~SimulatedMouseEvent();
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     SimulatedMouseEvent(const AtomicString& eventType, PassRefPtrWillBeRawPtr<AbstractView>, PassRefPtrWillBeRawPtr<Event> underlyingEvent);
 };
 
 class MouseEventDispatchMediator final : public EventDispatchMediator {
 public:
-    enum MouseEventType { SyntheticMouseEvent, NonSyntheticMouseEvent};
-    static PassRefPtrWillBeRawPtr<MouseEventDispatchMediator> create(PassRefPtrWillBeRawPtr<MouseEvent>, MouseEventType = NonSyntheticMouseEvent);
+    static PassRefPtrWillBeRawPtr<MouseEventDispatchMediator> create(PassRefPtrWillBeRawPtr<MouseEvent>);
 
 private:
-    explicit MouseEventDispatchMediator(PassRefPtrWillBeRawPtr<MouseEvent>, MouseEventType);
+    explicit MouseEventDispatchMediator(PassRefPtrWillBeRawPtr<MouseEvent>);
     MouseEvent& event() const;
 
     virtual bool dispatchEvent(EventDispatcher&) const override;
-    bool isSyntheticMouseEvent() const { return m_mouseEventType == SyntheticMouseEvent; }
-    MouseEventType m_mouseEventType;
 };
 
 DEFINE_EVENT_TYPE_CASTS(MouseEvent);
 
 } // namespace blink
 
 #endif // MouseEvent_h