Rip out browser-side RID caching for most visited items.

chrome/browser/ui/search/search_tab_helper.cc

Index: chrome/browser/ui/search/search_tab_helper.cc
diff --git a/chrome/browser/ui/search/search_tab_helper.cc b/chrome/browser/ui/search/search_tab_helper.cc
index 5086f81134839ebe362d9dfa161dbb4a6af203d6..f84abbe21c027d19f891a5be143590ff03eeace2 100644
--- a/chrome/browser/ui/search/search_tab_helper.cc
+++ b/chrome/browser/ui/search/search_tab_helper.cc
@@ -75,6 +75,15 @@ void SearchTabHelper::NavigationEntryUpdated() {
   UpdateMode();
 }
 
+bool SearchTabHelper::UpdateLastKnownMostVisitedItems(
+    const std::vector<InstantMostVisitedItem>& items) {
+  if (chrome::AreMostVisitedItemsEqual(items, last_known_most_visited_items_))
+    return false;
+
+  last_known_most_visited_items_ = items;
+  return true;
+}
+
 void SearchTabHelper::Observe(
     int type,
     const content::NotificationSource& source,