Changes favicon database to support storing bitmaps of different sizes for the same icon_url

chrome/browser/history/thumbnail_database.h

Index: chrome/browser/history/thumbnail_database.h
diff --git a/chrome/browser/history/thumbnail_database.h b/chrome/browser/history/thumbnail_database.h
index e2209e17a6af2405519645408b3f8c46e1721637..2364332e9e3e8752b43841be3efbbc2460e6ed04 100644
--- a/chrome/browser/history/thumbnail_database.h
+++ b/chrome/browser/history/thumbnail_database.h
@@ -257,6 +257,7 @@ class ThumbnailDatabase {
                            GetFaviconAfterMigrationToTopSites);
   FRIEND_TEST_ALL_PREFIXES(ThumbnailDatabaseTest, UpgradeToVersion4);
   FRIEND_TEST_ALL_PREFIXES(ThumbnailDatabaseTest, UpgradeToVersion5);
+  FRIEND_TEST_ALL_PREFIXES(ThumbnailDatabaseTest, UpgradeToVersion6);
   FRIEND_TEST_ALL_PREFIXES(HistoryBackendTest, MigrationIconMapping);
 
   // Creates the thumbnail table, returning true if the table already exists
@@ -284,6 +285,9 @@ class ThumbnailDatabase {
   // Adds support for sizes in favicon table.
   bool UpgradeToVersion5();
 
+  // Adds support for size in favicons table and removes sizes column.
+  bool UpgradeToVersion6();
+
   // Migrates the icon mapping data from URL database to Thumbnail database.
   // Return whether the migration succeeds.
   bool MigrateIconMappingData(URLDatabase* url_db);