Add a flag for enabling Chrome Web Store Gallery widget app

Add a flag for enabling Chrome Web Store Gallery widget app

This enables 'Printer detected' notification, clicking on which launches
Chrome Web Store widget  app showing list of apps that support the
detected printer.

BUG=439448
Committed: https://crrev.com/cd286fd7df51bd3a860d3d0549a5239bce759342
Cr-Commit-Position: refs/heads/master@{#330112}

[tbarzic, 2015-05-13 20:42:38]

tbarzic@chromium.org changed reviewers:
+ vitalybuka@chromium.org

[Vitaly Buka (NO REVIEWS), 2015-05-13 23:08:38]

lgtm

https://codereview.chromium.org/1123143004/diff/40001/chrome/app/chromeos_str...
File chrome/app/chromeos_strings.grdp (right):

https://codereview.chromium.org/1123143004/diff/40001/chrome/app/chromeos_str...
chrome/app/chromeos_strings.grdp:6366: Enables Chrome Web Store Gallery app that
searches Chrome Web Store for extensions that support a USB printer with
specific USB vendor ID - product ID pair.  </message>
Looks like to long sentence

[tbarzic, 2015-05-14 00:13:04]

https://codereview.chromium.org/1123143004/diff/40001/chrome/app/chromeos_str...
File chrome/app/chromeos_strings.grdp (right):

https://codereview.chromium.org/1123143004/diff/40001/chrome/app/chromeos_str...
chrome/app/chromeos_strings.grdp:6366: Enables Chrome Web Store Gallery app that
searches Chrome Web Store for extensions that support a USB printer with
specific USB vendor ID - product ID pair.  </message>
On 2015/05/13 23:08:38, Vitaly Buka wrote:
> Looks like to long sentence 

tried to break it up a bit.

[tbarzic, 2015-05-14 16:27:53]

tbarzic@chromium.org changed reviewers:
+ isherman@chromium.org

[Ilya Sherman, 2015-05-14 19:10:14]

histograms.xml lgtm

[tbarzic, 2015-05-15 15:53:45]

The CQ bit was checked by tbarzic@chromium.org

[tbarzic, 2015-05-15 15:53:46]

The patchset sent to the CQ was uploaded after l-g-t-m from
vitalybuka@chromium.org
Link to the patchset: https://codereview.chromium.org/1123143004/#ps80001
(title: "histograms")

[commit-bot: I haz the power, 2015-05-15 16:01:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1123143004/80001

[commit-bot: I haz the power, 2015-05-15 16:57:33]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2015-05-15 16:59:31]

Patchset 5 (id:??) landed as
https://crrev.com/cd286fd7df51bd3a860d3d0549a5239bce759342
Cr-Commit-Position: refs/heads/master@{#330112}