The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0010c9335a0d718e03ea3c0112f365a0dd380de2

commit 0010c9335a0d718e03ea3c0112f365a0dd380de2
Author: khmel <khmel@chromium.org>
Date: Thu Dec 01 22:00:07 2016

arc: Fix error when uninstalled default app appears in next session.

BUG=b/33252307
BUG= 670379 
TEST=Manually
TEST=Extended unit_tests

Review-Url: https://codereview.chromium.org/2549583003
Cr-Commit-Position: refs/heads/master@{#435731}

[modify] https://crrev.com/0010c9335a0d718e03ea3c0112f365a0dd380de2/chrome/browser/ui/app_list/arc/arc_app_list_prefs.cc
[modify] https://crrev.com/0010c9335a0d718e03ea3c0112f365a0dd380de2/chrome/browser/ui/app_list/arc/arc_app_unittest.cc

Requesting to merge once it is required for Kevin

Your change meets the bar and is auto-approved for M56 (branch: 2924)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dccb74f0cdc591dd2d26399e88276eda1833485a

commit dccb74f0cdc591dd2d26399e88276eda1833485a
Author: khmel <khmel@chromium.org>
Date: Mon Dec 05 19:01:26 2016

[Merge-M56] arc: Fix error when uninstalled default app appears in next session.

BUG=b/33252307
BUG= 670379 
TEST=Manually
TEST=Extended unit_tests

TBR=xiyuan@chromium.org
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2549583003
Cr-Commit-Position: refs/heads/master@{#435731}
(cherry picked from commit 0010c9335a0d718e03ea3c0112f365a0dd380de2)

Review-Url: https://codereview.chromium.org/2553783002
Cr-Commit-Position: refs/branch-heads/2924@{#338}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/dccb74f0cdc591dd2d26399e88276eda1833485a/chrome/browser/ui/app_list/arc/arc_app_list_prefs.cc
[modify] https://crrev.com/dccb74f0cdc591dd2d26399e88276eda1833485a/chrome/browser/ui/app_list/arc/arc_app_unittest.cc

56.0.2924.19/9000.21.0 kevin