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

chrome/browser/history/history.h

 // 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_H__
 #define CHROME_BROWSER_HISTORY_HISTORY_H__
 
 #include <string>
 #include <vector>
 
@@ skipping 83 matching lines @@
   // Must call Init after construction.
   explicit HistoryService(Profile* profile);
   // The empty constructor is provided only for testing.
   HistoryService();
   ~HistoryService();
 
   // Initializes the history service, returning true on success. On false, do
   // not call any other functions. The given directory will be used for storing
   // the history files. The BookmarkService is used when deleting URLs to
   // test if a URL is bookmarked; it may be NULL during testing.
-  bool Init(const FilePath& history_dir, BookmarkService* bookmark_service);
+  bool Init(const FilePath& history_dir, BookmarkService* bookmark_service) {
+    return Init(history_dir, bookmark_service, false);
+  }
 
   // Triggers the backend to load if it hasn't already, and then returns whether
   // it's finished loading.
   bool BackendLoaded();
 
   // Unloads the backend without actually shutting down the history service.
   // This can be used to temporarily reduce the browser process' memory
   // footprint.
   void UnloadBackend();
 
@@ skipping 423 matching lines @@
     PRIORITY_UI,      // The highest priority (must respond to UI events).
     PRIORITY_NORMAL,  // Normal stuff like adding a page.
     PRIORITY_LOW,     // Low priority things like indexing or expiration.
   };
 
   // Implementation of NotificationObserver.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
+  // Low-level Init().  Same as the public version, but adds a |no_db| parameter
+  // that is only set by unittests which causes the backend to not init its DB.
+  bool Init(const FilePath& history_dir,
+            BookmarkService* bookmark_service,
+            bool no_db);
+
   // Called by the HistoryURLProvider class to schedule an autocomplete, it
   // will be called back on the internal history thread with the history
   // database so it can query. See history_autocomplete.cc for a diagram.
   void ScheduleAutocomplete(HistoryURLProvider* provider,
                             HistoryURLProviderParams* params);
 
   // Broadcasts the given notification. This is called by the backend so that
   // the notification will be broadcast on the main thread.
   //
   // The |details_deleted| pointer will be sent as the "details" for the
@@ skipping 232 matching lines @@
   // The profile, may be null when testing.
   Profile* profile_;
 
   // Has the backend finished loading? The backend is loaded once Init has
   // completed.
   bool backend_loaded_;
 
   // Cached values from Init(), used whenever we need to reload the backend.
   FilePath history_dir_;
   BookmarkService* bookmark_service_;
+  bool no_db_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_H__