Add ClearHistory() to ContentSuggestionsService and its providers

components/ntp_snippets/content_suggestions_service_unittest.cc

Index: components/ntp_snippets/content_suggestions_service_unittest.cc
diff --git a/components/ntp_snippets/content_suggestions_service_unittest.cc b/components/ntp_snippets/content_suggestions_service_unittest.cc
index bf3f4a4d321a653b19fc67daf6c7d918b5c16f74..96563c506df2400970354284dab8c01172774764 100644
--- a/components/ntp_snippets/content_suggestions_service_unittest.cc
+++ b/components/ntp_snippets/content_suggestions_service_unittest.cc
@@ -100,6 +100,7 @@ class MockProvider : public ContentSuggestionsProvider {
     observer()->OnSuggestionInvalidated(this, category, suggestion_id);
   }
 
+  MOCK_METHOD2(ClearHistory, void(base::Time begin, base::Time end));
   MOCK_METHOD1(ClearCachedSuggestions, void(Category category));
   MOCK_METHOD2(GetDismissedSuggestionsForDebugging,
                void(Category category,
@@ -567,4 +568,12 @@ TEST_F(ContentSuggestionsServiceTest, ShouldPutBookmarksAtEndIfEmpty) {
   EXPECT_THAT(service()->GetCategories(), ElementsAre(remote, bookmarks));
 }
 
+TEST_F(ContentSuggestionsServiceTest, ShouldForwardClearHistory) {
+  Category category = FromKnownCategory(KnownCategories::DOWNLOADS);
+  MockProvider* provider = RegisterProvider(category);
+  base::Time begin, end;

[Marc Treib, 2016/08/30 09:50:18]

Initialize these to something sensible?

[vitaliii, 2016/08/30 11:04:22]

Done.

+  EXPECT_CALL(*provider, ClearHistory(begin, end));
+  service()->ClearHistory(begin, end);
+}
+
 }  // namespace ntp_snippets