Reviewed by Sam Weinig.

        <rdar://problem/6654255> crash due to null FrameView in EventHandler

        Lots of code was added to EventHandler that used view() and page() without
        null checking, but both of those can become null due to the frame lifetime.

        * page/EventHandler.cpp:
        (WebCore::EventHandler::handleMousePressEventSingleClick):
        (WebCore::EventHandler::eventMayStartDrag):
        (WebCore::EventHandler::handleAutoscroll):
        (WebCore::EventHandler::autoscrollTimerFired):
        (WebCore::EventHandler::setPanScrollCursor):
        (WebCore::EventHandler::allowDHTMLDrag):
        (WebCore::EventHandler::hitTestResultAtPoint):
        (WebCore::EventHandler::stopAutoscrollTimer):
        (WebCore::EventHandler::selectCursor):
        (WebCore::EventHandler::handleMousePressEvent):
        (WebCore::EventHandler::handleMouseMoveEvent):
        (WebCore::EventHandler::dispatchDragEvent):
        (WebCore::EventHandler::prepareMouseEvent):
        (WebCore::EventHandler::dispatchMouseEvent):
        (WebCore::EventHandler::handleWheelEvent):
        (WebCore::EventHandler::hoverTimerFired):
        (WebCore::EventHandler::keyEvent):
        (WebCore::EventHandler::dragHysteresisExceeded):
        (WebCore::EventHandler::shouldDragAutoNode):
        (WebCore::EventHandler::handleDrag):
        (WebCore::EventHandler::handleTextInputEvent):
        (WebCore::EventHandler::addPendingFrameUnloadEventCount):
        (WebCore::EventHandler::removePendingFrameUnloadEventCount):
        (WebCore::EventHandler::clearPendingFrameUnloadEventCount):
        (WebCore::EventHandler::addPendingFrameBeforeUnloadEventCount):
        (WebCore::EventHandler::removePendingFrameBeforeUnloadEventCount):
        (WebCore::EventHandler::clearPendingFrameBeforeUnloadEventCount):
        Added null checks for view() and page(). Made minor code cleanups.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@42190 268f45cc-cd09-0410-ab3c-d52691b4dbfc