[EFL] Don't assume AppWindow is always a NativeAppWindowDesktop in RuntimeUIDelegateDesktop
[EFL] Don't assume AppWindow is always a NativeAppWindowDesktop in RuntimeUIDelegateDesktop

On desktop version of efl, RuntimeUIDelegate is a
RuntimeUIDelegateDesktop. But AppWindow is a NativeAppWindowEfl. So we
cannot use SetLoadProgress or SetAddressURL methods.

hgl888/crosswalk-efl,hgl888/crosswalk-efl,hgl888/crosswalk-efl,crosswalk-project/crosswalk-efl,hgl888/crosswalk-efl,crosswalk-project/crosswalk-efl,crosswalk-project/crosswalk-efl,hgl888/crosswalk-efl,crosswalk-project/crosswalk-efl,crosswalk-project/crosswalk-efl,crosswalk-project/crosswalk-efl,crosswalk-project/crosswalk-efl,hgl888/crosswalk-efl,hgl888/crosswalk-efl