GitLab

+ Change color for icons from google_grey_600 to v2 Grey 800
+ Add custom attribute for tinting preference icons set from XML
+ Update icon color for Download spinner and location dialog

Bug: 834884, 863519
Change-Id: I7c9b61ad8983ef0fa01ad69065bdfe0b3baafa23
Reviewed-on: https://chromium-review.googlesource.com/1141128Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576124}