Revert of Change base::Value::ListStorage to std::vector<base::Value>

mojo/common/values_struct_traits.h

 // Copyright 2016 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_COMMON_VALUES_STRUCT_TRAITS_H_
 #define MOJO_COMMON_VALUES_STRUCT_TRAITS_H_
 
 #include "base/values.h"
 #include "mojo/common/values.mojom.h"
 #include "mojo/public/cpp/bindings/array_traits.h"
 #include "mojo/public/cpp/bindings/clone_traits.h"
 #include "mojo/public/cpp/bindings/map_traits.h"
 #include "mojo/public/cpp/bindings/struct_traits.h"
 #include "mojo/public/cpp/bindings/union_traits.h"
 
 namespace mojo {
 
 template <>
 struct ArrayTraits<base::ListValue> {
-  using Element = base::Value;
+  using Element = std::unique_ptr<base::Value>;
   using ConstIterator = base::ListValue::const_iterator;
 
   static size_t GetSize(const base::ListValue& input) {
     return input.GetSize();
   }
 
   static ConstIterator GetBegin(const base::ListValue& input) {
     return input.begin();
   }
 
@@ skipping 217 matching lines @@
                        base::Value>::dictionary_value(*value);
   }
 
   static bool Read(common::mojom::ValueDataView data,
                    std::unique_ptr<base::Value>* value);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_VALUES_STRUCT_TRAITS_H_