The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a260bac5596e34409d6e7842b98e8024772c2e59

commit a260bac5596e34409d6e7842b98e8024772c2e59
Author: gambard <gambard@chromium.org>
Date: Wed Mar 01 13:47:40 2017

Get Suggestions image only if it is not empty

This CL makes sure that the ContentSuggestions update the
ContentSuggestionsArticles only if an image has been fetched.

BUG= 697361 

Review-Url: https://codereview.chromium.org/2720423003
Cr-Commit-Position: refs/heads/master@{#453926}

[modify] https://crrev.com/a260bac5596e34409d6e7842b98e8024772c2e59/ios/chrome/browser/ui/content_suggestions/content_suggestions_article_item.h
[modify] https://crrev.com/a260bac5596e34409d6e7842b98e8024772c2e59/ios/chrome/browser/ui/content_suggestions/content_suggestions_article_item.mm
[modify] https://crrev.com/a260bac5596e34409d6e7842b98e8024772c2e59/ios/chrome/browser/ui/content_suggestions/content_suggestions_article_item_unittest.mm
[modify] https://crrev.com/a260bac5596e34409d6e7842b98e8024772c2e59/ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.mm