[NTP Client] Use the separate button style for the NoArticles status
Makes the articles and bookmarks sections use the same style of status
card when they have no snippets.
the hasMoreButton property of categories now only determines whether
the action item will be shown when there are suggestions to display.
This patch also lets the SuggestionsCategoryInfo be aware of the
current category it is describing, and moves various category specific
behaviours into the SuggestionsCategoryInfo class.
Preview:
https://goo.gl/photos/VhceT6cjvME6QS8m7
BUG=
649670
Committed:
https://crrev.com/ffa8e3905fed0b1df0d56ab6e4b17791b31cd171
Cr-Commit-Position: refs/heads/master@{#423517}