Add base:: to string16 in extensions/.

extensions/browser/test_management_policy.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 EXTENSIONS_BROWSER_TEST_MANAGEMENT_POLICY_H_
 #define EXTENSIONS_BROWSER_TEST_MANAGEMENT_POLICY_H_
 
 #include <string>
 
 #include "base/strings/string16.h"
@@ skipping 20 matching lines @@
 
   TestManagementPolicyProvider();
   explicit TestManagementPolicyProvider(int prohibited_actions);
 
   void SetProhibitedActions(int prohibited_actions);
   void SetDisableReason(Extension::DisableReason reason);
 
   virtual std::string GetDebugPolicyProviderName() const OVERRIDE;
 
   virtual bool UserMayLoad(const Extension* extension,
-                           string16* error) const OVERRIDE;
+                           base::string16* error) const OVERRIDE;
 
   virtual bool UserMayModifySettings(const Extension* extension,
-                                     string16* error) const OVERRIDE;
+                                     base::string16* error) const OVERRIDE;
 
   virtual bool MustRemainEnabled(const Extension* extension,
-                                 string16* error) const OVERRIDE;
+                                 base::string16* error) const OVERRIDE;
 
   virtual bool MustRemainDisabled(const Extension* extension,
                                   Extension::DisableReason* reason,
-                                  string16* error) const OVERRIDE;
+                                  base::string16* error) const OVERRIDE;
 
  private:
   bool may_load_;
   bool may_modify_status_;
   bool must_remain_enabled_;
   bool must_remain_disabled_;
   Extension::DisableReason disable_reason_;
 
-  string16 error_message_;
+  base::string16 error_message_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_TEST_MANAGEMENT_POLICY_H_