Quota: Send usage details in return value of estimate().

Change-Id: I85fd510b4245f966e32340b9d433f7d9b96b3810
Bug: 904000
Reviewed-on: https://chromium-review.googlesource.com/c/1303041
Commit-Queue: Jarryd Goodman <jarrydg@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611491}
23 files changed