From Joe @FS:
"I was just talking to a colligue about this issue. Regardless of how we do it, we have the issue of not including the non-editable marker in the offsets for Braille routing etc. We will need to know that we are in a list (perhaps an object attribute?) and how many characters to account for the list item at the beginning (another object attribute???) so that we can adjust the offsets for Braille routing and cursor tracking. Any time we have extra characters in the text which are non-navigable, we must somehow account for them so that the cursor blinks under the correct character. Whatever solution you come up with, will require work to ensure that the cursor is placed under the correct character when we output to Braille. Plese keep this in mind and let us know which route you take and how we can obtain the information necessary to keep cursor tracking correct.
For example, in a list item whose number is 100 folowed by a space before the main text of the line, the offset of the line really begins at 4 and the list item marker length is 4."

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dfe0ed4a9362cae34fe04555791f34b05cb21457

commit dfe0ed4a9362cae34fe04555791f34b05cb21457
Author: nektar <nektar@chromium.org>
Date: Wed Apr 12 03:33:26 2017

Switched to using |AXPosition| for calculating word and line boundaries on Windows.

These are enough changes for one patch but followup patches need to:
1. Switch to using |AXPosition| for character boundaries and get rid of ui::FindAccessibleTextBoundary.
2. Fix all bugs with SetSelection in Blink and get rid of Windows specific workarounds.
BUG= 672969 
R=dmazzoni@chromium.org
TESTED=manual testing, browser tests

Review-Url: https://codereview.chromium.org/2806773002
Cr-Commit-Position: refs/heads/master@{#463920}

[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/accessibility_win_browsertest.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/ax_platform_position.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility.h
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility_manager.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility_manager_unittest.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility_win.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility_win.h
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/content/browser/accessibility/browser_accessibility_win_unittest.cc
[modify] https://crrev.com/dfe0ed4a9362cae34fe04555791f34b05cb21457/ui/accessibility/ax_position.h