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- Use only 32 and 192 sizes
- Apply png optimizer.
- Use correct icons in icon_decode_request.cc

Bug: 879617
Test: manual
Change-Id: Icced1e403c75852b2143c695dd22032c3a9e4f8c
Reviewed-on: https://chromium-review.googlesource.com/1216084Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590420}