GstTask: hook up enter/leave/notify callbacks
GstTask: hook up enter/leave/notify callbacks

Hoop up the notify/enter/leave callbacks.

Distrotech/gstreamer,mparis/gstreamer,surround-io/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,justinjoy/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,drothlis/gstreamer,lovebug356/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,ahmedammar/platform_external_gst_gstreamer,krieger-od/gstreamer,lubosz/gstreamer,surround-io/gstreamer,ahmedammar/platform_external_gst_gstreamer,cfoch/gstreamer,krichter722/gstreamer,justinjoy/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,ensonic/gstreamer,magcius/gstreamer,lubosz/gstreamer,ahmedammar/platform_external_gst_gstreamer,Distrotech/gstreamer,collects/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,Lachann/gstreamer,centricular/gstreamer,Distrotech/gstreamer,StreamUtils/gstreamer,mrchapp/gstreamer,Lachann/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,mrchapp/gstreamer,ensonic/gstreamer,surround-io/gstreamer,mparis/gstreamer,lovebug356/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,krichter722/gstreamer,mrchapp/gstreamer,drothlis/gstreamer,Distrotech/gstreamer,surround-io/gstreamer,ylatuya/gstreamer,collects/gstreamer,cfoch/gstreamer,lubosz/gstreamer,magcius/gstreamer,lovebug356/gstreamer,shelsonjava/gstreamer,collects/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,mrchapp/gstreamer,krieger-od/gstreamer,Lachann/gstreamer,lovebug356/gstreamer,cfoch/gstreamer,drothlis/gstreamer,cablelabs/gstreamer,krieger-od/gstreamer,magcius/gstreamer,ahmedammar/platform_external_gst_gstreamer,Distrotech/gstreamer,ensonic/gstreamer,cfoch/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,drothlis/gstreamer,mparis/gstreamer,drothlis/gstreamer,krieger-od/gstreamer,magcius/gstreamer,jpakkane/gstreamer,ylatuya/gstreamer,mparis/gstreamer,surround-io/gstreamer,krieger-od/gstreamer,cfoch/gstreamer,lubosz/gstreamer,jpxiong/gstreamer,mrchapp/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,magcius/gstreamer,centricular/gstreamer,centricular/gstreamer,ylatuya/gstreamer,jpakkane/gstreamer,Lachann/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,collects/gstreamer,lubosz/gstreamer,ylatuya/gstreamer,jpakkane/gstreamer,centricular/gstreamer,ylatuya/gstreamer