ALT-SHIFT-A is used to return focus to any unfocused dialog, but the zoom dialog *disappears* after a moment. Therefore, instructing the user to press ALT-SHIFT-A to use the dialog is wrong. The zoom button in the Omnibox can be reached using F6 and TAB when Zoom is active (i.e. not 100%).

The correct solution is to remove the help alert from the zoom dialog that says to press ALT-SHIFT-A to focus it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3334f0abc56e80bad442ecbce42a341f1a6ef25e

commit 3334f0abc56e80bad442ecbce42a341f1a6ef25e
Author: Dana Fried <dfried@chromium.org>
Date: Wed Jan 09 02:14:40 2019

Suppress hotkey prompt when showing transient Zoom dialog.

Since the Zoom dialog disappears after a moment, instructing screen
reader users to press ALT-SHIFT-A to refocus it is misleading, since it
will likely be gone by the time they input the hotkey.

There are other accessible ways to access the screen zoom, so this is
not a problem.

Bug:  920005 
Change-Id: I42076474ade89c46eef68e1f6b30eb274c5efc82
Reviewed-on: https://chromium-review.googlesource.com/c/1401841
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Commit-Queue: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621000}
[modify] https://crrev.com/3334f0abc56e80bad442ecbce42a341f1a6ef25e/chrome/browser/ui/views/location_bar/location_bar_bubble_delegate_view.cc
[modify] https://crrev.com/3334f0abc56e80bad442ecbce42a341f1a6ef25e/chrome/browser/ui/views/location_bar/location_bar_bubble_delegate_view.h
[modify] https://crrev.com/3334f0abc56e80bad442ecbce42a341f1a6ef25e/chrome/browser/ui/views/location_bar/zoom_bubble_view.cc

Tried testing this issue on Windows 10 on the reported chrome 73.0.3665.0 and the latest M-73 73.0.3667.0 by following the below steps.

1. Launched Chrome 
2. Pressed CTRL-+ or CTRL-- to zoom the page
3. Pressed ALT-SHIFT-A
As we have not seen Magnifier dialog pops up and observed same behavior on both builds chrome 73.0.3665.0 and chrome 73.0.3667.0

Attached is the screen cast for reference.

Dana Fried@ Request you to check and confirm if anything is missed from our end in verifying the issue and help us to verify the fix on the latest M-73 build.

Thanks..!

Deleted: 920005.mp4 4.9 MB

	920005.mp4 4.9 MB View Download

This is as designed.

ALT-SHIFT-A is the hotkey for refocusing an inactive bubble.

As the Zoom bubble disappears after being shown briefly, it cannot be focused with ALT-SHIFT-A.

However, the screen reader message read when the bubble popped up had previously instructed the user to press ALT-SHIFT-A to focus the bubble, which was misleading. We have removed that additional message.

The user can still access the Zoom feature by pressing CTRL-+, CTRL--, and CTRL-0, as well as using F6 to access the main menu or the zoom icon in the omnibox (if the zoom is set to some other value than 100%) so there is no failure of accessibility.