Reviewed by Richard.

    Reviewed by Richard.

	<rdar://problem/4040776> Dashboard (Weather widget) is a memory hog

	Change things around so the event listeners for XMLHttpRequest
	mark their JS listener objects instead of holding a hard
	reference, to avoid an unbreakable reference cycle.

	* khtml/ecma/kjs_events.cpp:
        (JSAbstractEventListener::JSAbstractEventListener):
        (JSAbstractEventListener::~JSAbstractEventListener):
        (JSAbstractEventListener::handleEvent):
        (JSAbstractEventListener::eventListenerType):
        (JSUnprotectedEventListener::JSUnprotectedEventListener):
        (JSUnprotectedEventListener::~JSUnprotectedEventListener):
        (JSUnprotectedEventListener::listenerObj):
        (JSUnprotectedEventListener::windowObj):
        (JSUnprotectedEventListener::mark):
        (JSEventListener::JSEventListener):
        (JSEventListener::~JSEventListener):
        (JSEventListener::listenerObj):
        (JSEventListener::windowObj):
        (JSLazyEventListener::JSLazyEventListener):
        * khtml/ecma/kjs_events.h:
        * khtml/ecma/kjs_html.h:
        * khtml/ecma/kjs_window.cpp:
        (Window::getJSEventListener):
        (Window::getJSUnprotectedEventListener):
        * khtml/ecma/kjs_window.h:
        * khtml/ecma/xmlhttprequest.cpp:
        (KJS::XMLHttpRequest::putValue):
        (KJS::XMLHttpRequest::mark):
        * khtml/ecma/xmlhttprequest.h:
        * khtml/khtml_part.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8840 268f45cc-cd09-0410-ab3c-d52691b4dbfc