Add base:: to string16 in extensions/.

extensions/common/permissions/permission_message_provider.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_COMMON_PERMISSIONS_PERMISSION_MESSAGE_PROVIDER_H_
 #define EXTENSIONS_COMMON_PERMISSIONS_PERMISSION_MESSAGE_PROVIDER_H_
 
 #include <vector>
 
 #include "extensions/common/manifest.h"
@@ skipping 15 matching lines @@
   static const PermissionMessageProvider* Get();
 
   // Gets the localized permission messages that represent this set.
   // The set of permission messages shown varies by extension type.
   virtual PermissionMessages GetPermissionMessages(
       const PermissionSet* permissions,
       Manifest::Type extension_type) const = 0;
 
   // Gets the localized permission messages that represent this set (represented
   // as strings). The set of permission messages shown varies by extension type.
-  virtual std::vector<string16> GetWarningMessages(
+  virtual std::vector<base::string16> GetWarningMessages(
       const PermissionSet* permissions,
       Manifest::Type extension_type) const = 0;
 
   // Gets the localized permission details for messages that represent this set
   // (represented as strings). The set of permission messages shown varies by
   // extension type.
-  virtual std::vector<string16> GetWarningMessagesDetails(
+  virtual std::vector<base::string16> GetWarningMessagesDetails(
       const PermissionSet* permissions,
       Manifest::Type extension_type) const = 0;
 
   // Returns true if |new_permissions| has a greater privilege level than
   // |old_permissions|.
   // Whether certain permissions are considered varies by extension type.
   virtual bool IsPrivilegeIncrease(
       const PermissionSet* old_permissions,
       const PermissionSet* new_permissions,
       Manifest::Type extension_type) const = 0;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_PERMISSIONS_PERMISSION_MESSAGE_PROVIDER_H_