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As per crbug.com/788024 Comment 10 and other observations:
- Make error text darker (#D93025)
- Dialog width = 448 (for reals this time)
- Remove X (Close) button from upper right

Bug: 788024
Test: Get yourself into some kinda pin-needin' situation and confirm the
Harmonious nature of the pin-requestin' dialog.

Change-Id: I7da3bffa3ff91434f651dd316a245cdf8d3f91a1
Reviewed-on: https://chromium-review.googlesource.com/1118609Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Greg Levin <glevin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574961}