Handle device scale factor properly in cc::MirrorLayerImpl

To avoid applying device scale factor twice,
MirrorLayerImpl::AppendQuads() should first undo the scale factor
applied to draw transform as it will be applied later again (similar to
what LayerImpl::PopulateScaledSharedQuadState() does).

BUG=947565

Change-Id: I7e8bdb21ca9883f6639166dfa9b7b58fc33b90dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1685892
Commit-Queue: Mohsen Izadi <mohsen@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#674954}
11 files changed