Revert "Revert "Add a new GrResourceCache purging mechanism for purging unused resources.""

This reverts commit 20c322ef0cd04cf8e2592879d05d9f4e6cb19596.

Change-Id: I6df9a8594484837672308dc2c21c7c29b76ffa2c
Reviewed-on: https://skia-review.googlesource.com/10013
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
8 files changed