Unittest for fix to allow navigation when there is no history DB....

chrome/browser/history/history_backend.h

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_
 
 #include <utility>
 
 #include "base/file_path.h"
 #include "base/scoped_ptr.h"
@@ skipping 80 matching lines @@
   // This constructor is fast and does no I/O, so can be called at any time.
   HistoryBackend(const FilePath& history_dir,
                  Delegate* delegate,
                  BookmarkService* bookmark_service);
 
   ~HistoryBackend();
 
   // Must be called after creation but before any objects are created. If this
   // fails, all other functions will fail as well. (Since this runs on another
   // thread, we don't bother returning failure.)
-  void Init();
+  //
+  // |force_fail| can be set during unittests to unconditionally fail to init.
+  void Init(bool force_fail);
 
   // Notification that the history system is shutting down. This will break
   // the refs owned by the delegate and any pending transaction so it will
   // actually be deleted.
   void Closing();
 
   // See NotifyRenderProcessHostDestruction.
   void NotifyRenderProcessHostDestruction(const void* host);
 
   // Navigation ----------------------------------------------------------------
@@ skipping 397 matching lines @@
   // Publishes the history to all indexers which are registered to receive
   // history data from us. Can be NULL if there are no listeners.
   scoped_ptr<HistoryPublisher> history_publisher_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryBackend);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_