Add ability to uninstantiate lazy proxies after every flush.

Bug: skia:
Change-Id: Id32540cda54a9c5e3e6cb721776699be3cc8ac1a
Reviewed-on: https://skia-review.googlesource.com/113263
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
15 files changed