Reviewed by Martin Robinson.

        [GTK] Remove G_CONST_RETURN usage
        https://bugs.webkit.org/show_bug.cgi?id=62673

        Change G_CONST_RETURN for a simple "const" throughout the
        codebase, since G_CONST_RETURN is deprecated now. This should be
        totally equivalent since for all practical purposes the macro is
        always expanded to const.

        * webkit/webkitapplicationcache.cpp:
        (webkit_application_cache_get_database_directory_path): use const
        instead of G_CONST_RETURN.
        * webkit/webkitapplicationcache.h:
        * webkit/webkiticondatabase.cpp:
        (webkit_icon_database_get_path): ditto.
        * webkit/webkiticondatabase.h:
        * webkit/webkitnetworkrequest.cpp:
        (webkit_network_request_get_uri): ditto.
        * webkit/webkitnetworkrequest.h:
        * webkit/webkitnetworkresponse.cpp:
        (webkit_network_response_get_uri): ditto.
        * webkit/webkitnetworkresponse.h:
        * webkit/webkitsecurityorigin.cpp:
        (webkit_security_origin_get_protocol): ditto.
        (webkit_security_origin_get_host): ditto.
        * webkit/webkitsecurityorigin.h:
        * webkit/webkitwebdatabase.cpp:
        (webkit_web_database_get_name): ditto.
        (webkit_web_database_get_display_name): ditto.
        (webkit_web_database_get_filename): ditto.
        (webkit_get_web_database_directory_path): ditto.
        * webkit/webkitwebdatabase.h:
        * webkit/webkitwebdatasource.cpp:
        (webkit_web_data_source_get_encoding): ditto.
        (webkit_web_data_source_get_unreachable_uri): ditto.
        * webkit/webkitwebdatasource.h:
        * webkit/webkitwebframe.cpp:
        (webkit_web_frame_get_title): ditto.
        (webkit_web_frame_get_uri): ditto.
        (webkit_web_frame_get_name): ditto.
        * webkit/webkitwebframe.h:
        * webkit/webkitwebhistoryitem.cpp:
        (webkit_web_history_item_get_title): ditto.
        (webkit_web_history_item_get_alternate_title): ditto.
        (webkit_web_history_item_get_uri): ditto.
        (webkit_web_history_item_get_original_uri): ditto.
        (webkit_web_history_item_get_target): ditto.
        * webkit/webkitwebhistoryitem.h:
        * webkit/webkitwebhistoryitemprivate.h:
        * webkit/webkitwebnavigationaction.cpp:
        (webkit_web_navigation_action_get_target_frame): ditto.
        * webkit/webkitwebnavigationaction.h:
        * webkit/webkitwebresource.cpp:
        (webkit_web_resource_get_uri): ditto.
        (webkit_web_resource_get_mime_type): ditto.
        (webkit_web_resource_get_encoding): ditto.
        (webkit_web_resource_get_frame_name): ditto.
        * webkit/webkitwebresource.h:
        * webkit/webkitwebsettings.cpp:
        (webkit_web_settings_get_user_agent): ditto.
        * webkit/webkitwebsettings.h:
        * webkit/webkitwebview.cpp:
        (webkit_web_view_get_title): ditto.
        (webkit_web_view_get_uri): ditto.
        (webkit_web_view_get_icon_uri): ditto.
        * webkit/webkitwebview.h:
        * webkit/webkitwebviewcommon.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@88872 268f45cc-cd09-0410-ab3c-d52691b4dbfc