Add explicit base namespace to string16 users.

chrome/common/extensions/api/sockets/sockets_manifest_data.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 CHROME_COMMON_EXTENSIONS_API_SOCKETS_SOCKETS_MANIFEST_DATA_H_
 #define CHROME_COMMON_EXTENSIONS_API_SOCKETS_SOCKETS_MANIFEST_DATA_H_
 
 #include <vector>
 
 #include "base/strings/string16.h"
@@ skipping 21 matching lines @@
   // specified.
   static SocketsManifestData* Get(const Extension* extension);
 
   static bool CheckRequest(const Extension* extension,
                            const content::SocketPermissionRequest& request);
 
   // Tries to construct the info based on |value|, as it would have appeared in
   // the manifest. Sets |error| and returns an empty scoped_ptr on failure.
   static scoped_ptr<SocketsManifestData> FromValue(
       const base::Value& value,
-      string16* error);
+      base::string16* error);
 
   const SocketsManifestPermission* permission() const {
     return permission_.get();
   }
 
  private:
   scoped_ptr<SocketsManifestPermission> permission_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_API_SOCKETS_SOCKETS_MANIFEST_DATA_H_