Reland "Ash Tray: Fix tray bubble opening on another display."

This is a reland of 464d6f6e5243d9b754cd2caa629fd83f3b3a6ec6

Original change's description:
> Ash Tray: Fix tray bubble opening on another display.
> 
> An off-by-one error caused the anchor bounds of the bubble to be inside
> the bounds of the next display rather than the current display, causing
> the bubble to be shown on the wrong display.
> 
> This regression was caused by http://crrev/c/1474278.
> 
> TEST=manually verified & new unit test case
> BUG=937420
> 
> Change-Id: I6a248a785ea1ee36bdbb8ab75853efba71938272
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1526383
> Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
> Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
> Auto-Submit: Vladislav Kaznacheev <kaznacheev@chromium.org>
> Reviewed-by: Michael Wasserman <msw@chromium.org>
> Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#641288}

Bug: 937420
Change-Id: Ib49e87142e988276aae5ba31a05f30713f765fe9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1528061
Auto-Submit: Tim Song <tengs@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641594}