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We want to plumb frame visibility change to GRC. Before that, we want to
understand the volume of IPC. This patch adds histogram to record the frame
visibility when it's changed.

BUG=790680

Change-Id: Ib798308bf18473c1432cbe651ac9217714115b9a
Reviewed-on: https://chromium-review.googlesource.com/807351Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: lpy <lpy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522002}