Enable downloads UI for NTP-saved pages.

Enable downloads UI for NTP-saved pages.

This patch fixes 3 problems:
* The NTP code is gated on a flag in offline pages that is only for
  testing.
* The NTP namespace is marked as "Supported by Download", which allows
  the download home to show these pages, and the download notification
  to work for these pages.

BUG=662105
Review-Url: https://codereview.chromium.org/2473953006
Cr-Commit-Position: refs/heads/master@{#429727}
(cherry picked from commit b637ece132d7e0a975f0780724f8354297552fcd)

Committed: https://chromium.googlesource.com/chromium/src/+/bb84a1f6864dc62f8ed4fe48a64d111c1bbea774

[dewittj, 2016-11-07 21:35:54]

Description was changed from

==========
Enable downloads UI for NTP-saved pages.

This patch fixes 3 problems:
* The NTP code is gated on a flag in offline pages that is only for
  testing.
* The NTP namespace is marked as "Supported by Download", which allows
  the download home to show these pages, and the download notification
  to work for these pages.

BUG=662105

Review-Url: https://codereview.chromium.org/2473953006
Cr-Commit-Position: refs/heads/master@{#429727}
(cherry picked from commit b637ece132d7e0a975f0780724f8354297552fcd)
==========

to

==========
Enable downloads UI for NTP-saved pages.

This patch fixes 3 problems:
* The NTP code is gated on a flag in offline pages that is only for
  testing.
* The NTP namespace is marked as "Supported by Download", which allows
  the download home to show these pages, and the download notification
  to work for these pages.

BUG=662105

Review-Url: https://codereview.chromium.org/2473953006
Cr-Commit-Position: refs/heads/master@{#429727}
(cherry picked from commit b637ece132d7e0a975f0780724f8354297552fcd)

Committed:
https://chromium.googlesource.com/chromium/src/+/bb84a1f6864dc62f8ed4fe48a64d...
==========

[dewittj, 2016-11-07 21:35:56]

Committed patchset #1 (id:1) manually as
bb84a1f6864dc62f8ed4fe48a64d111c1bbea774 (tree was closed).