The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ce2e11f2565db306765cc6f6412cf5bfb158fb70

commit ce2e11f2565db306765cc6f6412cf5bfb158fb70
Author: patricialor <patricialor@chromium.org>
Date: Fri May 26 01:25:32 2017

a11y: Exclude children of nested keyboard accessible controls from a11y tree.

Currently, children of keyboard accessible controls, such as the Labels inside
LabelButtons, are not hidden from the accessibility tree. This is not useful
because the user only cares about the element that has focus, not any children
inside it, which are implementation details. Set any children of keyboard
accessible controls to have ignored roles, which indicates to the OS (works for
Windows, Mac, and Linux) that the ignored element should be excluded from the
accessibility tree.

BUG= 610589 , 723574 
TEST=On Mac: Open the XCode Accessibility Inspector. On Windows: Open the
Windows SDK 'Inspect.exe' and make sure the icon for 'Watch Focus' is selected.
Then (on Mac, hover over; on Windows, focus) a views::LabelButton (e.g. on the
HTTP Authentication dialog). It should report an empty set of children and its
role ("Type"/"accessibilityRole" on Mac; "Role"/"ControlType" on Windows) should
say it is a button.

Review-Url: https://codereview.chromium.org/2119413004
Cr-Commit-Position: refs/heads/master@{#474867}

[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/accessibility/platform/ax_platform_node_auralinux.cc
[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/accessibility/platform/ax_platform_node_mac.mm
[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/accessibility/platform/ax_platform_node_win.cc
[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/views/accessibility/native_view_accessibility_base.cc
[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/views/accessibility/native_view_accessibility_unittest.cc
[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/views/view.h
[modify] https://crrev.com/ce2e11f2565db306765cc6f6412cf5bfb158fb70/ui/views/widget/native_widget_mac_accessibility_unittest.mm

Thank you for reporting this :)

(To clarify, the solution we implemented for this was to not show the children of complex Views, as opposed to making sure those children have the correct accessibility information, which is what was suggested in the "expected behaviour" section of the bug report. So the bookmark button should show up as a single a11y element, not a button with an image and text inside, with the correct a11y information on the image and text, which was what #c3 implemented.)