Ifdef out the parts of navigation_controller.h that are not supported on iOS.

content/public/browser/navigation_controller.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_NAVIGATION_CONTROLLER_H_
 #define CONTENT_PUBLIC_BROWSER_NAVIGATION_CONTROLLER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 296 matching lines @@
 
   // Removing of entries -------------------------------------------------------
 
   // Removes the entry at the specified |index|.  This call dicards any pending
   // and transient entries.  If the index is the last committed index, this does
   // nothing and returns false.
   virtual void RemoveEntryAtIndex(int index) = 0;
 
   // Random --------------------------------------------------------------------
 
+  // Session storage depends on dom_storage that depends on WebKit::WebString,
+  // which cannot be used on iOS.
+#if !defined(OS_IOS)
   // Returns all the SessionStorageNamespace objects that this
   // NavigationController knows about.
   virtual const SessionStorageNamespaceMap&
       GetSessionStorageNamespaceMap() const = 0;
 
   // TODO(ajwong): Remove this once prerendering, instant, and session restore
   // are migrated.
   virtual SessionStorageNamespace* GetDefaultSessionStorageNamespace() = 0;
+#endif
 
   // Sets the max restored page ID this NavigationController has seen, if it
   // was restored from a previous session.
   virtual void SetMaxRestoredPageID(int32 max_id) = 0;
 
   // Returns the largest restored page ID seen in this navigation controller,
   // if it was restored from a previous session.  (-1 otherwise)
   virtual int32 GetMaxRestoredPageID() const = 0;
 
   // Returns true if a reload happens when activated (SetActive(true) is
@@ skipping 29 matching lines @@
   virtual void CopyStateFromAndPrune(NavigationController* source) = 0;
 
   // Removes all the entries except the active entry. If there is a new pending
   // navigation it is preserved.
   virtual void PruneAllButActive() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_NAVIGATION_CONTROLLER_H_