Fix for <rdar://problem/5126393> REGRESSION (r19672-19697): Safari drag image drags at original size (13261)

        Added logic to ensure that when we create the drag image
        we're looking at the rendered image size.

        * page/DragController.cpp:
        (WebCore::DragController::doImageDrag):
          Pass the rendered image size to fitDragImageToMaxSize

        * platform/DragImage.cpp:
        (WebCore::fitDragImageToMaxSize):
           Need to do scaling relative to rendered image size

        * platform/DragImage.h:
           scaleDragImage needs x and y scales to allow for them to be
           scaled seperately on a page

        * platform/gdk/DragImageGdk.cpp:
        (WebCore::scaleDragImage):
           Prevent build bustage

        * platform/mac/DragImageMac.mm:
        (WebCore::scaleDragImage):
           scale width and height independently

        * platform/qt/DragImageQt.cpp:
        (WebCore::scaleDragImage):
           Prevent build bustage



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@21185 268f45cc-cd09-0410-ab3c-d52691b4dbfc