[Modern] Fixes Icon Color for Preferences Toolbar

Sets tint for delete icon to default icon color
Darkens help and feedback color to default icon color
Picture in bug link

Bug: 863796
Change-Id: I08c3a5a2a261d1725a96500919ea634b253636bd
Reviewed-on: https://chromium-review.googlesource.com/1141059
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Daniel Park <danielpark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575828}
3 files changed