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

Source/core/input/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 1677 matching lines @@
     if (!view)
         return false;
 
     RefPtrWillBeRawPtr<MouseEvent> me = MouseEvent::create(eventType,
         true, true, m_frame->document()->domWindow(),
         0, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(),
         event.movementDelta().x(), event.movementDelta().y(),
         event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(),
         0, MouseEvent::platformModifiersToButtons(event.modifiers()), nullptr, dataTransfer);
 
-    dragTarget->dispatchEvent(me.get(), IGNORE_EXCEPTION);
+    dragTarget->dispatchMouseEvent(me.get());
+
     return me->defaultPrevented();
 }
 
 static bool targetIsFrame(Node* target, LocalFrame*& frame)
 {
     if (!isHTMLFrameElementBase(target))
         return false;
 
     // Cross-process drag and drop is not yet supported.
     if (toHTMLFrameElementBase(target)->contentFrame() && !toHTMLFrameElementBase(target)->contentFrame()->isLocalFrame())
@@ skipping 2470 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink