Reviewed by Sam Weinig

        https://bugs.webkit.org/show_bug.cgi?id=21967

        For some platforms the GeolocationService must be suspended and resumed.

        * page/Geolocation.cpp:
        (WebCore::Geolocation::clearWatch): now uses Geolocation::hasListeners()
        (WebCore::Geolocation::suspend): calls GeolocationService::suspend() if there are listeners
        (WebCore::Geolocation::resume): calls GeolocationService::resume() if there are listeners
        (WebCore::Geolocation::geolocationServicePositionChanged): now uses Geolocation::hasListeners()
        * page/Geolocation.h:
        (WebCore::Geolocation::hasListeners): Indicates of the Geolocation has interested GeolocationService listeners
        * platform/GeolocationService.h:
        (WebCore::GeolocationService::suspend): empty implementation
        (WebCore::GeolocationService::resume): empty implementation

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@38018 268f45cc-cd09-0410-ab3c-d52691b4dbfc