Create ReadingListSuggestionsProvider

components/ntp_snippets/category_rankers/constant_category_ranker.cc

Index: components/ntp_snippets/category_rankers/constant_category_ranker.cc
diff --git a/components/ntp_snippets/category_rankers/constant_category_ranker.cc b/components/ntp_snippets/category_rankers/constant_category_ranker.cc
index 8ba04ab61dbf24518db0d5cd8726816c1edddbeb..83cd92aea8ef4add915612b12df1f2ea61a190fd 100644
--- a/components/ntp_snippets/category_rankers/constant_category_ranker.cc
+++ b/components/ntp_snippets/category_rankers/constant_category_ranker.cc
@@ -73,6 +73,7 @@ ConstantCategoryRanker::GetKnownCategoriesDefaultOrder() {
   switch (choice) {
     case CategoryOrderChoice::GENERAL:
       categories.push_back(KnownCategories::PHYSICAL_WEB_PAGES);
+      categories.push_back(KnownCategories::READING_LIST);
       categories.push_back(KnownCategories::DOWNLOADS);
       categories.push_back(KnownCategories::RECENT_TABS);
       categories.push_back(KnownCategories::FOREIGN_TABS);
@@ -80,6 +81,7 @@ ConstantCategoryRanker::GetKnownCategoriesDefaultOrder() {
       categories.push_back(KnownCategories::ARTICLES);
       break;
     case CategoryOrderChoice::EMERGING_MARKETS_ORIENTED:
+      categories.push_back(KnownCategories::READING_LIST);

[Marc Treib, 2017/03/17 14:44:00]

The "EMERGING_MARKETS_ORIENTED" order explicitly has ARTICLES at the top, so I'd
move this below. (Not that it'll matter in practice, but still)

[gambard, 2017/03/20 08:32:39]

Well, what if we want Reading List on top for emerging market? What is the
difference between emerging market and general?

[Marc Treib, 2017/03/20 09:55:26]

We don't :)

I'll provide some more context out-of-band.

       categories.push_back(KnownCategories::ARTICLES);
       categories.push_back(KnownCategories::DOWNLOADS);
       categories.push_back(KnownCategories::BOOKMARKS);
@@ -91,7 +93,7 @@ ConstantCategoryRanker::GetKnownCategoriesDefaultOrder() {
   }
 
   static_assert(
-      static_cast<size_t>(KnownCategories::LOCAL_CATEGORIES_COUNT) == 5,
+      static_cast<size_t>(KnownCategories::LOCAL_CATEGORIES_COUNT) == 6,
       "All local KnownCategories must be present in all orders.");
 
   // Other remote categories will be ordered after these depending on when