[Icons NTP] Make Local NTP render largeIconUrl instead of thumbnail, if available.

[Icons NTP] Make Local NTP render largeIconUrl instead of thumbnail, if available.

This is a minimalistic way to display large icons on local NTP for testing.
The code looks for the "largeIconUrl" data, which only becomes available
beyind flag. If not found then use thumbnail as before; otherwise large icons.
New NTP styles are not implemented in this CL.

BUG=467712
Committed: https://crrev.com/8341df4812ce9c197c321fbf0b3d028bf2d55160
Cr-Commit-Position: refs/heads/master@{#321247}

[huangs, 2015-03-17 20:55:34]

huangs@chromium.org changed reviewers:
+ beaudoin@chromium.org, mathp@chromium.org, rogerm@chromium.org

[huangs, 2015-03-17 20:55:35]

PTAL.

[beaudoin, 2015-03-17 23:29:45]

Nice and simple way to implement this! Well done.

LGTM

[Mathieu, 2015-03-18 13:37:01]

lgtm

[huangs, 2015-03-18 22:58:47]

Committing.  Will handle updating fserb@'s new NTP soon.

[huangs, 2015-03-18 22:58:52]

The CQ bit was checked by huangs@chromium.org

[commit-bot: I haz the power, 2015-03-18 22:59:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1013173003/1

[commit-bot: I haz the power, 2015-03-19 00:18:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-19 00:19:00]

Patchset 1 (id:??) landed as
https://crrev.com/8341df4812ce9c197c321fbf0b3d028bf2d55160
Cr-Commit-Position: refs/heads/master@{#321247}