Fix extensions compile issues for Android on sync_unit_tests.

chrome/browser/extensions/extension_warning_set.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 CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SET_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SET_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 60 matching lines @@
   static void NotifyWarningsOnUI(void* profile_id,
                                  std::set<std::string> extension_ids,
                                  WarningType warning_type);
 
  protected:
   // Virtual for testing.
   virtual void NotifyWarningsChanged();
 
  private:
   typedef std::set<ExtensionWarning>::const_iterator const_iterator;
+  typedef std::set<ExtensionWarning>::iterator iterator;
 
   // Shows or hides the warning badge on the wrench menu depending on whether
   // any non-suppressed warnings exist.
   void UpdateWarningBadge();
 
   // Currently existing warnings.
   std::set<ExtensionWarning> warnings_;
 
   // Warnings that do not trigger a badge on the wrench menu.
   std::set<ExtensionWarning> badge_suppressions_;
 
   Profile* profile_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SET_H_