Some fleshing out the mojo based localstorage implementation.

mojo/public/cpp/bindings/array.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 MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_
 
 #include <stddef.h>
 #include <string.h>
 #include <algorithm>
@@ skipping 277 matching lines @@
   static std::set<E> Convert(const Array<T>& input) {
     std::set<E> result;
     if (!input.is_null()) {
       for (size_t i = 0; i < input.size(); ++i)
         result.insert(TypeConverter<E, T>::Convert(input[i]));
     }
     return result;
   }
 };
 
+// Less than operator to allow Arrays as keys in std maps and sets.
+template <typename T>
+inline bool operator<(const Array<T>& a, const Array<T>& b) {
+  if (a.is_null())
+    return !b.is_null();
+  if (b.is_null())
+    return false;
+  return a.storage() < b.storage();
+}
+
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_