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* Take rotation into account
* Fix when display zoom is applised.
  The overscan is dp but w/o display zoom. To convert to DP in UI coordinates,
  it first have to be converted to pixel then divided by the scale factor.

Bug: 1021292
Test: unittests + manual
Change-Id: I82785b74013c82e9eb20a7714510e62a421337db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1896374Reviewed-by: Jun Mukai <mukai@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712763}