Reviewed by Gustavo Noronha.

        Try to sanitize a bit the geometry management of plugins.

        Stop doing contradictory things in updatePluginWidget (we were at
        the same time pretending the geometry setting was delayed until
        ::paint and setting the geometry not once but twice) and just set
        it any time the windowRect or clipRect for the plugin has changed.

        This is closer to what the Mac port does, and fixes instances of
        the plugins not being drawn until the window is resized or
        scrolled. Other than that all manual and layout tests seems to
        still work.

        * plugins/gtk/PluginViewGtk.cpp:
        (WebCore::PluginView::updatePluginWidget):
        (WebCore::PluginView::setNPWindowIfNeeded):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@55186 268f45cc-cd09-0410-ab3c-d52691b4dbfc