Unpin deleted URLs + better deleting algorithm.

chrome/browser/history/top_sites.h

Index: chrome/browser/history/top_sites.h
diff --git a/chrome/browser/history/top_sites.h b/chrome/browser/history/top_sites.h
index 99d20ce98b51a89761ebd06ec25dc06a12638598..09d0af06810d3a0828c4643514428a0ad008b141 100644
--- a/chrome/browser/history/top_sites.h
+++ b/chrome/browser/history/top_sites.h
@@ -142,6 +142,7 @@ class TopSites : public NotificationObserver,
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, RealDatabase);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, MockDatabase);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, DeleteNotifications);
+  FRIEND_TEST_ALL_PREFIXES(TopSitesTest, PinnedURLsDeleted);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, GetUpdateDelay);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, Migration);
   FRIEND_TEST_ALL_PREFIXES(TopSitesTest, QueueingRequestsForTopSites);
@@ -183,6 +184,9 @@ class TopSites : public NotificationObserver,
   void OnThumbnailAvailable(CancelableRequestProvider::Handle handle,
                             scoped_refptr<RefCountedBytes> thumbnail);
 
+  // Sets canonical_urls_ from top_sites_.
+  void GenerateCanonicalURLs();
+
   // Saves the set of the top URLs visited by this user. The 0th item is the
   // most popular.
   // DANGER! This will clear all data from the input argument.