Create Private Data for InMemoryURLIndex (in Preparation for SQLite Cache)

chrome/browser/autocomplete/history_quick_provider.h

Index: chrome/browser/autocomplete/history_quick_provider.h
===================================================================
--- chrome/browser/autocomplete/history_quick_provider.h	(revision 107888)
+++ chrome/browser/autocomplete/history_quick_provider.h	(working copy)
@@ -81,7 +81,10 @@
       bool is_url);
 
   // Only for use in unittests.  Takes ownership of |index|.
-  void SetIndexForTesting(history::InMemoryURLIndex* index);
+  void set_index(history::InMemoryURLIndex* index) {
+    index_for_testing_.reset(index);
+  }
+
   AutocompleteInput autocomplete_input_;
   std::string languages_;