1. see  crbug.com/707933 . With that bug fixed, a user that encounters either an email or url text field will automatically be switched to an 8-dot braille table of the user's choice. In U.S. english comptuer braille, the @ sign is written as dots 4-7. To input an @ sign, these keys need to be pressed together.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/72bb94a66c02d96c6a4b258ce7e8c5ebb0272273

commit 72bb94a66c02d96c6a4b258ce7e8c5ebb0272273
Author: dtseng <dtseng@chromium.org>
Date: Wed Apr 12 22:10:01 2017

Ignore unknown focusable nodes if they have children

BUG=710892, 707927 
TEST=navigate by object in Gmail's compose view. Verify that object navigation doesn't skip the "unknown" node which contains the contents of the form (e.g. to, from, etc). Also, verify that ChromeVox never lands on the unknown node directly and does not mention it in ancestry summarization.

Review-Url: https://codereview.chromium.org/2817713002
Cr-Commit-Position: refs/heads/master@{#464168}

[modify] https://crrev.com/72bb94a66c02d96c6a4b258ce7e8c5ebb0272273/chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d8bfbee9bffdb2827fc28d84dc44c13c349ce317

commit d8bfbee9bffdb2827fc28d84dc44c13c349ce317
Author: dtseng <dtseng@chromium.org>
Date: Tue Apr 18 14:28:16 2017

Improve Learn Mode for braille

- output dots ... chord, when we don't have a mapping and a user presses a chord combination
- when a user types a dot pattern, back-translate the pattern using the current braille table and output.
For example, if a user presses dot 4 in English computer braille, they will hear "@".
- when a user types a chord that maps to a command or modifier, they will receive that as output.
For example, "control" (dots 2-5 chord), "backspace" (dot 7 chord)

TEST=open Learn Mode. Press various braille keys.
BUG= 707927 , 707940 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2819273002
Cr-Commit-Position: refs/heads/master@{#465231}

[modify] https://crrev.com/d8bfbee9bffdb2827fc28d84dc44c13c349ce317/chrome/browser/resources/chromeos/chromevox/chromevox/background/kbexplorer.js

This should be fixed; please verify.