GitLab

FloatingMenuButton only reuses little logic of TopShortcutButton. e.g,
set the tooltip. And TopShortcutButton named as the top shortcut button
at the system tray menu. Make FloatingMenuButton as ImageButton instead.
And AutoclickScrollCloseButton to be a FloatingMenuButton to reuse its
logic.

Then simplify TopShortcutButton to have only one constructor.

Bug: 1131543
Change-Id: I68bc2ed7e535b45319c47271c2dfc4cd8f0e2626
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485563
Commit-Queue: Min Chen <minch@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819888}