Instead the refcount is done via callbacks. This allows Surface to
ignore this refcounting which will be useful in a follow-up CL.

BUG=angleproject:891

Change-Id: I39b028476e0e3ab1837c033e1121ea21e54d7970
Reviewed-on: https://chromium-review.googlesource.com/291651Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>