Support action button to fetch more content suggestions

components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc

Index: components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
diff --git a/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc b/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
index f77fcd4229788a661994fbd9fea079fd9098298d..e9043a2f99a6f57d4e33bd1d4e3af018889f6a6e 100644
--- a/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
+++ b/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
@@ -92,7 +92,11 @@ CategoryStatus BookmarkSuggestionsProvider::GetCategoryStatus(
 CategoryInfo BookmarkSuggestionsProvider::GetCategoryInfo(Category category) {
   return CategoryInfo(
       l10n_util::GetStringUTF16(IDS_NTP_BOOKMARK_SUGGESTIONS_SECTION_HEADER),
-      ContentSuggestionsCardLayout::MINIMAL_CARD);
+      ContentSuggestionsCardLayout::MINIMAL_CARD, true);
+}
+
+void BookmarkSuggestionsProvider::FetchMoreSuggestions(Category category) {
+  // Ignored.

[Marc Treib, 2016/08/10 09:40:31]

NOTREACHED()
since we don't expect this to get called?

[Philipp Keck, 2016/08/10 13:14:46]

No. We will have global reload actions. Currently that's only *maybe* through
the status card, depending on UX decisions. But after M54 we will introduce a
global refresh actions that just needs to go out to all providers. So this must
ignore, not fail.

[Marc Treib, 2016/08/10 13:19:04]

But "refresh" is not quite the same as "fetch more".

[Philipp Keck, 2016/08/10 15:16:41]

True. I removed the whole FetchMoreSuggestions thing for now, as it won't be
used. Lots of ignore methods and such will just be confusing for M54. Will add
it back in after the feature freeze.

 }
 
 void BookmarkSuggestionsProvider::DismissSuggestion(