GitLab

This CL supports manually scale of ImageSkia for different
representations, which could deliver good visual effect for reps other
than 1x and 2x.

Bug: 840641
Test: manual
Change-Id: I7c131a76297dd565065ff67213b90349ff00206d
Reviewed-on: https://chromium-review.googlesource.com/1081408Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Qiang Xu <warx@google.com>
Cr-Commit-Position: refs/heads/master@{#568192}