[Chrome OS] Implement the device wallpaper policy.

[Chrome OS] Implement the device wallpaper policy.

This CL implements the device policy to allow the domain admins to
set a device level policy controlled wallpaper for an enterprise
managed device. The device policy wallpaper will display on the login
screen all the time without requiring a user to log in. The device
policy wallpaper is also set as a user's wallpaper if there is no user
policy controlled wallpaper and the user hasn't changed his default
wallpaper in a user's session.

Detailed description of the expected behavior is described as below:

- In the login screen, if the device wallpaper policy present, use the
device policy wallpaper, otherwise, check if user-selected wallpaper
exists, if so, use the user-selected wallpaper, otherwise use OEM
default wallpaper.

- Within a user session, if the user wallpaper policy present, user the
user policy wallpaper, otherwise, check if user has changed his default
wallpaper before, if so, use user-slected wallpaper, otherwise, check
if the device wallpaper policy present, if so, use the device policy
wallpaper, otherwise, use OEM default wallpaper.

This is a follow-up CL of https://codereview.chromium.org/2544693002/.

BUG=475998
Committed: https://crrev.com/3e55b65c0a88cee2107208b3bde6eaadf0ccc743
Cr-Commit-Position: refs/heads/master@{#438667}

[xdai1, 2016-12-13 23:15:31]

xdai@chromium.org changed reviewers:
+ alemate@chromium.org, isherman@chromium.org

[xdai1, 2016-12-13 23:15:31]

alemate@, isherman@, could you help review this CL please? Thanks!
alemate@: all
isherman@: tools/metrics/histograms/histograms.xml

[Ilya Sherman, 2016-12-14 01:34:58]

histograms.xml lgtm

[Alexander Alekseev, 2016-12-14 03:47:13]

lgtm

[xdai1, 2016-12-14 20:47:52]

The CQ bit was checked by xdai@chromium.org

[xdai1, 2016-12-14 20:47:52]

The patchset sent to the CQ was uploaded after l-g-t-m from
alemate@chromium.org, isherman@chromium.org
Link to the patchset: https://codereview.chromium.org/2572793003/#ps20001
(title: "Rebase.")

[commit-bot: I haz the power, 2016-12-14 20:48:25]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-14 22:36:06]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-14 22:36:07]

Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[xdai1, 2016-12-14 22:44:01]

The CQ bit was checked by xdai@chromium.org

[commit-bot: I haz the power, 2016-12-14 22:44:27]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-14 23:20:14]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1481755441431040,
"parent_rev": "7f4b77ea7a77a3034d6256e407c8a93ba27bdd7d", "commit_rev":
"f7702629c75982adf3019b8d4b785a85ec6d4338"}

[commit-bot: I haz the power, 2016-12-14 23:20:45]

Description was changed from

==========
[Chrome OS] Implement the device wallpaper policy.

This CL implements the device policy to allow the domain admins to
set a device level policy controlled wallpaper for an enterprise
managed device. The device policy wallpaper will display on the login
screen all the time without requiring a user to log in. The device
policy wallpaper is also set as a user's wallpaper if there is no user
policy controlled wallpaper and the user hasn't changed his default
wallpaper in a user's session.

Detailed description of the expected behavior is described as below:

- In the login screen, if the device wallpaper policy present, use the
device policy wallpaper, otherwise, check if user-selected wallpaper
exists, if so, use the user-selected wallpaper, otherwise use OEM
default wallpaper.

- Within a user session, if the user wallpaper policy present, user the
user policy wallpaper, otherwise, check if user has changed his default
wallpaper before, if so, use user-slected wallpaper, otherwise, check
if the device wallpaper policy present, if so, use the device policy
wallpaper, otherwise, use OEM default wallpaper.

This is a follow-up CL of https://codereview.chromium.org/2544693002/.

BUG=475998
==========

to

==========
[Chrome OS] Implement the device wallpaper policy.

This CL implements the device policy to allow the domain admins to
set a device level policy controlled wallpaper for an enterprise
managed device. The device policy wallpaper will display on the login
screen all the time without requiring a user to log in. The device
policy wallpaper is also set as a user's wallpaper if there is no user
policy controlled wallpaper and the user hasn't changed his default
wallpaper in a user's session.

Detailed description of the expected behavior is described as below:

- In the login screen, if the device wallpaper policy present, use the
device policy wallpaper, otherwise, check if user-selected wallpaper
exists, if so, use the user-selected wallpaper, otherwise use OEM
default wallpaper.

- Within a user session, if the user wallpaper policy present, user the
user policy wallpaper, otherwise, check if user has changed his default
wallpaper before, if so, use user-slected wallpaper, otherwise, check
if the device wallpaper policy present, if so, use the device policy
wallpaper, otherwise, use OEM default wallpaper.

This is a follow-up CL of https://codereview.chromium.org/2544693002/.

BUG=475998

Review-Url: https://codereview.chromium.org/2572793003
==========

[commit-bot: I haz the power, 2016-12-14 23:20:46]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-12-14 23:22:45]

Description was changed from

==========
[Chrome OS] Implement the device wallpaper policy.

This CL implements the device policy to allow the domain admins to
set a device level policy controlled wallpaper for an enterprise
managed device. The device policy wallpaper will display on the login
screen all the time without requiring a user to log in. The device
policy wallpaper is also set as a user's wallpaper if there is no user
policy controlled wallpaper and the user hasn't changed his default
wallpaper in a user's session.

Detailed description of the expected behavior is described as below:

- In the login screen, if the device wallpaper policy present, use the
device policy wallpaper, otherwise, check if user-selected wallpaper
exists, if so, use the user-selected wallpaper, otherwise use OEM
default wallpaper.

- Within a user session, if the user wallpaper policy present, user the
user policy wallpaper, otherwise, check if user has changed his default
wallpaper before, if so, use user-slected wallpaper, otherwise, check
if the device wallpaper policy present, if so, use the device policy
wallpaper, otherwise, use OEM default wallpaper.

This is a follow-up CL of https://codereview.chromium.org/2544693002/.

BUG=475998

Review-Url: https://codereview.chromium.org/2572793003
==========

to

==========
[Chrome OS] Implement the device wallpaper policy.

This CL implements the device policy to allow the domain admins to
set a device level policy controlled wallpaper for an enterprise
managed device. The device policy wallpaper will display on the login
screen all the time without requiring a user to log in. The device
policy wallpaper is also set as a user's wallpaper if there is no user
policy controlled wallpaper and the user hasn't changed his default
wallpaper in a user's session.

Detailed description of the expected behavior is described as below:

- In the login screen, if the device wallpaper policy present, use the
device policy wallpaper, otherwise, check if user-selected wallpaper
exists, if so, use the user-selected wallpaper, otherwise use OEM
default wallpaper.

- Within a user session, if the user wallpaper policy present, user the
user policy wallpaper, otherwise, check if user has changed his default
wallpaper before, if so, use user-slected wallpaper, otherwise, check
if the device wallpaper policy present, if so, use the device policy
wallpaper, otherwise, use OEM default wallpaper.

This is a follow-up CL of https://codereview.chromium.org/2544693002/.

BUG=475998

Committed: https://crrev.com/3e55b65c0a88cee2107208b3bde6eaadf0ccc743
Cr-Commit-Position: refs/heads/master@{#438667}
==========

[commit-bot: I haz the power, 2016-12-14 23:22:46]

Patchset 2 (id:??) landed as
https://crrev.com/3e55b65c0a88cee2107208b3bde6eaadf0ccc743
Cr-Commit-Position: refs/heads/master@{#438667}