Added some public methods to web::NavigationController.

ios/web/public/navigation_manager.h

 // Copyright 2013 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 IOS_WEB_PUBLIC_NAVIGATION_MANAGER_H_
 #define IOS_WEB_PUBLIC_NAVIGATION_MANAGER_H_
 
 #include "ios/web/public/browser_url_rewriter.h"
 
 namespace web {
@@ skipping 33 matching lines @@
 
   // Removes the transient and pending NavigationItems.
   virtual void DiscardNonCommittedItems() = 0;
 
   // Adds |rewriter| to a transient list of URL rewriters.  Transient URL
   // rewriters will be executed before the rewriters already added to the
   // BrowserURLRewriter singleton, and the list will be cleared after the next
   // attempted page load.  |rewriter| must not be null.
   virtual void AddTransientURLRewriter(
       BrowserURLRewriter::URLRewriter rewriter) = 0;
+
+  // Returns the number of items in the NavigationManager, excluding
+  // pending and transient entries.
+  virtual int GetEntryCount() const = 0;
+
+  // Returns the committed NavigationItem at |index|.
+  virtual NavigationItem* GetItemAtIndex(size_t index) const = 0;
+
+  // Returns the index from which web would go back/forward or reload.
+  virtual int GetCurrentEntryIndex() const = 0;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_NAVIGATION_MANAGER_H_