Switch base::Value typemapping to be by value instead of by unique_ptr.

mojo/common/values_struct_traits.h

Index: mojo/common/values_struct_traits.h
diff --git a/mojo/common/values_struct_traits.h b/mojo/common/values_struct_traits.h
index befcf3a6ea2816dd56e56f0a50933d9cec3548e0..9ef63b68da2cf84c74a95911b8a28d081f582afb 100644
--- a/mojo/common/values_struct_traits.h
+++ b/mojo/common/values_struct_traits.h
@@ -17,7 +17,7 @@ namespace mojo {
 
 template <>
 struct ArrayTraits<base::ListValue> {
-  using Element = std::unique_ptr<base::Value>;
+  using Element = base::Value;
   using ConstIterator = base::ListValue::const_iterator;
 
   static size_t GetSize(const base::ListValue& input) {
@@ -30,37 +30,20 @@ struct ArrayTraits<base::ListValue> {
 
   static void AdvanceIterator(ConstIterator& iterator) { ++iterator; }
 
-  static const Element& GetValue(ConstIterator& iterator) { return *iterator; }
+  static const Element& GetValue(ConstIterator& iterator) { return **iterator; }
 };
 
 template <>
 struct StructTraits<common::mojom::ListValueDataView, base::ListValue> {
+  static bool Read(common::mojom::ListValueDataView data,
+                   base::ListValue* value);
+
   static const base::ListValue& values(const base::ListValue& value) {
     return value;
   }
 };
 
 template <>
-struct StructTraits<common::mojom::ListValueDataView,
-                    std::unique_ptr<base::ListValue>> {
-  static bool IsNull(const std::unique_ptr<base::ListValue>& value) {
-    return !value;
-  }
-
-  static void SetToNull(std::unique_ptr<base::ListValue>* value) {
-    value->reset();
-  }
-
-  static const base::ListValue& values(
-      const std::unique_ptr<base::ListValue>& value) {
-    return *value;
-  }
-
-  static bool Read(common::mojom::ListValueDataView data,
-                   std::unique_ptr<base::ListValue>* value);
-};
-
-template <>
 struct MapTraits<base::DictionaryValue> {
   using Key = std::string;
   using Value = base::Value;
@@ -84,6 +67,9 @@ struct MapTraits<base::DictionaryValue> {
 template <>
 struct StructTraits<common::mojom::DictionaryValueDataView,
                     base::DictionaryValue> {
+  static bool Read(common::mojom::DictionaryValueDataView data,
+                   base::DictionaryValue* value);
+
   static const base::DictionaryValue& values(
       const base::DictionaryValue& value) {
     return value;
@@ -91,32 +77,9 @@ struct StructTraits<common::mojom::DictionaryValueDataView,
 };
 
 template <>
-struct StructTraits<common::mojom::DictionaryValueDataView,
-                    std::unique_ptr<base::DictionaryValue>> {
-  static bool IsNull(const std::unique_ptr<base::DictionaryValue>& value) {
-    return !value;
-  }
-
-  static void SetToNull(std::unique_ptr<base::DictionaryValue>* value) {
-    value->reset();
-  }
-
-  static const base::DictionaryValue& values(
-      const std::unique_ptr<base::DictionaryValue>& value) {
-    return *value;
-  }
-  static bool Read(common::mojom::DictionaryValueDataView data,
-                   std::unique_ptr<base::DictionaryValue>* value);
-};
-
-template <>
-struct CloneTraits<std::unique_ptr<base::DictionaryValue>, false> {
-  static std::unique_ptr<base::DictionaryValue> Clone(
-      const std::unique_ptr<base::DictionaryValue>& input);
-};
-
-template <>
 struct UnionTraits<common::mojom::ValueDataView, base::Value> {
+  static bool Read(common::mojom::ValueDataView data, base::Value* value);
+
   static common::mojom::ValueDataView::Tag GetTag(const base::Value& data) {
     switch (data.GetType()) {
       case base::Value::Type::NONE:
@@ -196,62 +159,6 @@ struct UnionTraits<common::mojom::ValueDataView, base::Value> {
   }
 };
 
-template <>
-struct UnionTraits<common::mojom::ValueDataView, std::unique_ptr<base::Value>> {
-  static bool IsNull(const std::unique_ptr<base::Value>& value) {
-    return !value;
-  }
-
-  static void SetToNull(std::unique_ptr<base::Value>* value) { value->reset(); }
-
-  static common::mojom::ValueDataView::Tag GetTag(
-      const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::GetTag(
-        *value);
-  }
-
-  static common::mojom::NullValuePtr null_value(
-      const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::null_value(
-        *value);
-  }
-  static bool bool_value(const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::bool_value(
-        *value);
-  }
-  static int32_t int_value(const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::int_value(
-        *value);
-  }
-  static double double_value(const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::double_value(
-        *value);
-  }
-  static base::StringPiece string_value(
-      const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::string_value(
-        *value);
-  }
-  static mojo::ConstCArray<uint8_t> binary_value(
-      const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::binary_value(
-        *value);
-  }
-  static const base::ListValue& list_value(
-      const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView, base::Value>::list_value(
-        *value);
-  }
-  static const base::DictionaryValue& dictionary_value(
-      const std::unique_ptr<base::Value>& value) {
-    return UnionTraits<common::mojom::ValueDataView,
-                       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_