Remove Clone() from CannedBrowsingData*Helper classes

chrome/browser/browsing_data/browsing_data_indexed_db_helper.h

Index: chrome/browser/browsing_data/browsing_data_indexed_db_helper.h
diff --git a/chrome/browser/browsing_data/browsing_data_indexed_db_helper.h b/chrome/browser/browsing_data/browsing_data_indexed_db_helper.h
index f1880063ffabbbafe4a0bed0e1a335d305b6262e..2ce44ea03a0d6e48d6fb02254038d8d98f31a22f 100644
--- a/chrome/browser/browsing_data/browsing_data_indexed_db_helper.h
+++ b/chrome/browser/browsing_data/browsing_data_indexed_db_helper.h
@@ -96,11 +96,6 @@ class CannedBrowsingDataIndexedDBHelper
   explicit CannedBrowsingDataIndexedDBHelper(
       content::IndexedDBContext* context);
 
-  // Return a copy of the IndexedDB helper. Only one consumer can use the
-  // StartFetching method at a time, so we need to create a copy of the helper
-  // every time we instantiate a cookies tree model for it.
-  CannedBrowsingDataIndexedDBHelper* Clone();
-
   // Add a indexed database to the set of canned indexed databases that is
   // returned by this helper.
   void AddIndexedDB(const GURL& origin,