Stop history search going on beyond the start of history....

chrome/browser/history/history_backend.h

Index: chrome/browser/history/history_backend.h
===================================================================
--- chrome/browser/history/history_backend.h	(revision 11260)
+++ chrome/browser/history/history_backend.h	(working copy)
@@ -144,7 +144,6 @@
 
   void GetVisitCountToHost(scoped_refptr<GetVisitCountToHostRequest> request,
                            const GURL& url);
-
   // Computes the most recent URL(s) that the given canonical URL has
   // redirected to and returns true on success. There may be more than one
   // redirect in a row, so this function will fill the given array with the
@@ -461,6 +460,9 @@
   // This keeps track of that higher-resolution timestamp.
   base::Time last_recorded_time_;
 
+  // Timestamp of the first entry in our database.
+  base::Time first_recorded_time_;
+
   // When non-NULL, this is the task that should be invoked on
   MessageLoop* backend_destroy_message_loop_;
   Task* backend_destroy_task_;