Shorten NotifySwap path for offscreen rendering

Shorten NotifySwap path for offscreen rendering

This commit shortens NotifySwap path by removing some
of the changes in upstream code.

w/o patch:
SkiaOutputSurfaceImpl->Display(OutputSurfaceClient)->
RootCompositorFrameSinkImpl(DisplayClient)->FrameSinkManagerImpl->
HostFrameSinkManager(FrameSinkManagerClient)->
DelegatedFrameHost(HostFrameSinkClient)->
DelegatedFrameHostClientAura(DelegatedFrameHostClient)->
RenderWidgetHostViewAura->RWHVAuraOffscreenHelperEfl

with patch:
SkiaOutputSurfaceImpl->Display(OutputSurfaceClient)->
RootCompositorFrameSinkImpl(DisplayClient)->
HostDisplayClient(mojom::DisplayClient)->Compositor->
CompositorObserverEfl(CompositorObserver)->
RWHVAuraOffscreenHelperEfl

Reference: https://review.tizen.org/gerrit/287806/

Change-Id: I5dbfad3a6bb8460804045c6a8b66bae1f74130ac
Signed-off-by: Chandan Padhi <c.padhi@samsung.com>