Fix NTP after rotation in the tab switcher.

Fix NTP after rotation in the tab switcher.

Repro steps:
1.) Open NTP (in tabbed mode)
2.) Rotate landscape and scroll toolbar to top
3.) Long press on an NTP item and open in incognito
4.) Open tab switcher and switch back to normal stack
5.) Rotate to portrait
6.) Select NTP

Turns out in this case an onScrollChanged is not broadcast
from the scroll view so we need to push one ourselves.

BUG=548088
Committed: https://crrev.com/d0a28226d7ba73ae2240dcbe12af1d8f2ed3b6c1
Cr-Commit-Position: refs/heads/master@{#360734}

[Ted C, 2015-11-19 22:05:51]

tedchoc@chromium.org changed reviewers:
+ newt@chromium.org

[Ted C, 2015-11-19 22:05:52]

PTAL

[newt (away), 2015-11-19 22:27:23]

lgtm

[Ted C, 2015-11-19 22:28:19]

The CQ bit was checked by tedchoc@chromium.org

[commit-bot: I haz the power, 2015-11-19 22:28:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1460503005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1460503005/1

[commit-bot: I haz the power, 2015-11-20 00:18:31]

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

[commit-bot: I haz the power, 2015-11-20 00:18:32]

Try jobs failed on following builders:
  linux_android_rel_ng on tryserver.chromium.linux (JOB_FAILED, no build URL)

[Ted C, 2015-11-20 01:46:01]

The CQ bit was checked by tedchoc@chromium.org

[commit-bot: I haz the power, 2015-11-20 01:46:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1460503005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1460503005/1

[commit-bot: I haz the power, 2015-11-20 03:30:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-20 03:32:03]

Patchset 1 (id:??) landed as
https://crrev.com/d0a28226d7ba73ae2240dcbe12af1d8f2ed3b6c1
Cr-Commit-Position: refs/heads/master@{#360734}