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
Review URL: https://codereview.chromium.org/1460503005

Cr-Commit-Position: refs/heads/master@{#360734}

Committed: https://chromium.googlesource.com/chromium/src/+/3e432b9da840998bac45dafb233e5f4b8c9ecae1

[Ted C, 2016-01-11 22:17:09]

Description was changed from

==========
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

Review URL: https://codereview.chromium.org/1460503005

Cr-Commit-Position: refs/heads/master@{#360734}
==========

to

==========
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

Review URL: https://codereview.chromium.org/1460503005

Cr-Commit-Position: refs/heads/master@{#360734}

Committed:
https://chromium.googlesource.com/chromium/src/+/3e432b9da840998bac45dafb233e...
==========

[Ted C, 2016-01-11 22:17:10]

Committed patchset #1 (id:1) manually as
3e432b9da840998bac45dafb233e5f4b8c9ecae1.