Please apply appropriate OS labels. Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2c6de2bebee569ee216b4b6688625147601c2a23

commit 2c6de2bebee569ee216b4b6688625147601c2a23
Author: dtseng <dtseng@chromium.org>
Date: Fri Feb 10 18:46:27 2017

Ensure ChromeVox defaults to ChromeVox Next on upgrade

In an upgrade scenario, local storage persists. As a result, key/values for 'useNext' retain their defaults (as set by prefs.js).

In m56, we want useNext to default to true.

Ensure this by adding a new pref, 'useClassic', that is ensured to be a new key on upgrade.

BUG= 690939 
TEST=have a profile with the previous key/value local storage set. Apply this patch, and ensure newly built Chrome *defaults* to Next on launch. Use this build in Learn Mode and ensure key mappings respect mode (e.g. classic keys described when in classic mode).

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2693463002
Cr-Commit-Position: refs/heads/master@{#449670}

[modify] https://crrev.com/2c6de2bebee569ee216b4b6688625147601c2a23/chrome/browser/resources/chromeos/chromevox/chromevox/background/kbexplorer.js
[modify] https://crrev.com/2c6de2bebee569ee216b4b6688625147601c2a23/chrome/browser/resources/chromeos/chromevox/chromevox/background/prefs.js
[modify] https://crrev.com/2c6de2bebee569ee216b4b6688625147601c2a23/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
[modify] https://crrev.com/2c6de2bebee569ee216b4b6688625147601c2a23/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
[modify] https://crrev.com/2c6de2bebee569ee216b4b6688625147601c2a23/chrome/browser/resources/chromeos/chromevox/cvox2/background/panel.js

Approving merge to M57 Chrome OS.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f

commit e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f
Author: David Tseng <dtseng@chromium.org>
Date: Fri Feb 10 21:35:22 2017

Merge to m57: Ensure ChromeVox defaults to ChromeVox Next on upgrade

In an upgrade scenario, local storage persists. As a result, key/values for 'useNext' retain their defaults (as set by prefs.js).

In m56, we want useNext to default to true.

Ensure this by adding a new pref, 'useClassic', that is ensured to be a new key on upgrade.

BUG= 690939 
TEST=have a profile with the previous key/value local storage set. Apply this patch, and ensure newly built Chrome *defaults* to Next on launch. Use this build in Learn Mode and ensure key mappings respect mode (e.g. classic keys described when in classic mode).
TBR=dtseng@chromium.org

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2693463002
Cr-Commit-Position: refs/heads/master@{#449670}
(cherry picked from commit 2c6de2bebee569ee216b4b6688625147601c2a23)

Review-Url: https://codereview.chromium.org/2687153004 .
Cr-Commit-Position: refs/branch-heads/2987@{#454}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[modify] https://crrev.com/e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f/chrome/browser/resources/chromeos/chromevox/chromevox/background/kbexplorer.js
[modify] https://crrev.com/e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f/chrome/browser/resources/chromeos/chromevox/chromevox/background/prefs.js
[modify] https://crrev.com/e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
[modify] https://crrev.com/e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
[modify] https://crrev.com/e5b6c571ad2b50b9f849c52db91e3a6bfcd5d63f/chrome/browser/resources/chromeos/chromevox/cvox2/background/panel.js

Please note the request remaining for a merge to m56. Please advise if more info is needed.