Revert "Notify OverviewProxyService of scrim colors"

Bug: 130451254
Test: manual

This reverts commit d9b9847ad63ae0a97552de757dee8102f0d8cc0c.

Reason for revert: found a better way to extract scrim colors without going through OverviewProxy

Change-Id: Iac97fee4d9b15757f7211889f6c370757c0870e3
4 files changed