The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2ff29563c5b0619e3722c74af2fe3afa18819999

commit 2ff29563c5b0619e3722c74af2fe3afa18819999
Author: dtseng <dtseng@chromium.org>
Date: Mon Oct 24 18:48:56 2016

Fix editable text selection

We need to special-case setting selections when the focused node is itself editable.
- make no adjustments for the selected node; placing selection outside of the editable content causes key presses to go to the page
- if we are trying to select the entire node, set the selection index to 0 (placing selection at the beginning of the node); otherwise, use the character offset

TEST=move to a text field or content editable via ChromeVox commands; verify typing works to echo the keys. Furthermore, verify that in a content editable with headings, links, etc, jump commands move the selection. Finally, verify ChromeVox text movement commands (e.g. next character), moves selection in single line editables.
BUG= 656349 , 658045 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2442503008
Cr-Commit-Position: refs/heads/master@{#427106}

[modify] https://crrev.com/2ff29563c5b0619e3722c74af2fe3afa18819999/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js

verified on 56.0.2903.0