Add ClearHistory() to ContentSuggestionsService and its providers

components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc

Index: components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc
diff --git a/components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc b/components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc
index ee03cebf90033f43995851d23d2d7bfe0a089483..84a6cdc09f77ecd82649b6e10dd498b51bd69275 100644
--- a/components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc
+++ b/components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc
@@ -86,6 +86,14 @@ void PhysicalWebPageSuggestionsProvider::FetchSuggestionImage(
       FROM_HERE, base::Bind(callback, gfx::Image()));
 }
 
+void PhysicalWebPageSuggestionsProvider::ClearHistory(
+    base::Time begin,
+    base::Time end,
+    base::Callback<bool(const GURL& url)> filter) {
+  // TODO(vitaliii): Implement when dismissed suggestions are supported. See
+  // crbug.com/641321.
+}
+
 void PhysicalWebPageSuggestionsProvider::ClearCachedSuggestions(
     Category category) {
   // Ignored