Add explicit base namespace to string16 users.

chrome/common/extensions/api/storage/storage_schema_manifest_handler.cc

 // 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.
 
 #include "chrome/common/extensions/api/storage/storage_schema_manifest_handler.h"
 
 #include <string>
 #include <vector>
 
 #include "base/file_util.h"
@@ skipping 47 matching lines @@
   std::string content;
   if (!base::ReadFileToString(file, &content)) {
     *error = base::StringPrintf("Can't read %s", file.value().c_str());
     return policy::Schema();
   }
   return policy::Schema::Parse(content, error);
 }
 #endif
 
 bool StorageSchemaManifestHandler::Parse(Extension* extension,
-                                         string16* error) {
+                                         base::string16* error) {
   std::string path;
   if (!extension->manifest()->GetString(kStorageManagedSchema, &path)) {
     *error = ASCIIToUTF16(
         base::StringPrintf("%s must be a string", kStorageManagedSchema));
     return false;
   }
   return true;
 }
 
 bool StorageSchemaManifestHandler::Validate(
     const Extension* extension,
     std::string* error,
     std::vector<InstallWarning>* warnings) const {
 #if defined(ENABLE_CONFIGURATION_POLICY)
   return GetSchema(extension, error).valid();
 #else
   return true;
 #endif
 }
 
 const std::vector<std::string> StorageSchemaManifestHandler::Keys() const {
   return SingleKey(kStorageManagedSchema);
 }
 
 }  // namespace extensions