mardini, WDYT?

Dismissing the suggestion should *not* remove it from the reading list, but it should remove it from future NTPs. It could be shown again on explicit "update" events, e.g. if the users explicitly refreshes it (I don't know if such an action exists).

I'm not sure if the dismissal should propagate to other devices. I think we generally don't do that.

As discussed offline, dismissal should remove it only from future NTPs but leave it on its dedicated surface (on device or on other devices).

Ok, the behavior will be:
- Dismissal on swipe left only (no long press)
- Once dismissed the Reading List entry no longer appear on the NTPs of the device on which it has been dismissed
- The entry is not dismissed on the NTP of other synced device
- The entry is unchanged on the dedicated Reading List surface

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0043013229fffab3555daf28c64ee27521209d7b

commit 0043013229fffab3555daf28c64ee27521209d7b
Author: gambard <gambard@chromium.org>
Date: Tue Apr 11 14:05:38 2017

Track if a ReadingListEntry has been dismissed

This CL adds a field to the ReadingListEntry, saved only on the device, to
track if the entry has been dismissed from the NTP.
The only way to change the extra information is to use the model, allowing
the data to be stored.

BUG= 707730 

Review-Url: https://codereview.chromium.org/2806213004
Cr-Commit-Position: refs/heads/master@{#463615}

[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/proto/reading_list.proto
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_entry.cc
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_entry.h
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_entry_unittest.cc
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_model.h
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_model_impl.cc
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_model_impl.h
[modify] https://crrev.com/0043013229fffab3555daf28c64ee27521209d7b/components/reading_list/core/reading_list_model_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1f0337d7e2d5fc26c25f264e83a726d56ba4ee0d

commit 1f0337d7e2d5fc26c25f264e83a726d56ba4ee0d
Author: gambard <gambard@chromium.org>
Date: Wed Apr 12 11:00:41 2017

ReadingListProvider handles dismissal

Implements the logic of the dismissal of Reading List entries in their provider.

BUG= 707730 ,  702241 

Review-Url: https://codereview.chromium.org/2815623002
Cr-Commit-Position: refs/heads/master@{#463989}

[modify] https://crrev.com/1f0337d7e2d5fc26c25f264e83a726d56ba4ee0d/components/ntp_snippets/reading_list/reading_list_suggestions_provider.cc
[modify] https://crrev.com/1f0337d7e2d5fc26c25f264e83a726d56ba4ee0d/components/ntp_snippets/reading_list/reading_list_suggestions_provider.h
[modify] https://crrev.com/1f0337d7e2d5fc26c25f264e83a726d56ba4ee0d/components/ntp_snippets/reading_list/reading_list_suggestions_provider_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c6f978a173b3be6cb45f306ec00d666911d0ee40

commit c6f978a173b3be6cb45f306ec00d666911d0ee40
Author: gambard <gambard@chromium.org>
Date: Wed Jun 07 12:42:09 2017

Implement the swipe-to-dismiss gesture

The swipe to dismiss gesture allows the user to remove a suggestion from the
list.

BUG= 707730 

Change-Id: I89b6f8c52b8bd8fd3e49ee17436049d422dd3a78
Reviewed-on: https://chromium-review.googlesource.com/527073
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Louis Romero <lpromero@chromium.org>
Cr-Commit-Position: refs/heads/master@{#477619}
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/chrome/browser/content_suggestions/content_suggestions_mediator.h
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/chrome/browser/content_suggestions/content_suggestions_mediator.mm
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.h
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.mm
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/chrome/browser/ui/content_suggestions/content_suggestions_data_source.h
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm
[modify] https://crrev.com/c6f978a173b3be6cb45f306ec00d666911d0ee40/ios/showcase/content_suggestions/sc_content_suggestions_data_source.mm

Verified in 61.0.3128.0 canary, iPhone 6 plus iOS 10.2.1, iPad mini 10.3 beta 7

Followed comment #4.
Looks good.