Show a warning when the history files can't be read correctly....

chrome/browser/history/history_backend.h

Index: chrome/browser/history/history_backend.h
===================================================================
--- chrome/browser/history/history_backend.h	(revision 30544)
+++ chrome/browser/history/history_backend.h	(working copy)
@@ -52,9 +52,8 @@
    public:
     virtual ~Delegate() {}
 
-    // Called when the database is from a future version of the product and can
-    // not be used.
-    virtual void NotifyTooNew() = 0;
+    // Called when the database cannot be read correctly for some reason.
+    virtual void NotifyProfileError(int message_id) = 0;
 
     // Sets the in-memory history backend. The in-memory backend is created by
     // the main backend. For non-unit tests, this happens on the background