bindings: Add support for the record<K,V> WebIDL type.

third_party/WebKit/Source/bindings/core/v8/IDLTypes.h

Index: third_party/WebKit/Source/bindings/core/v8/IDLTypes.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/IDLTypes.h b/third_party/WebKit/Source/bindings/core/v8/IDLTypes.h
index 611a0c04b81aee15c442a22bea42ee60886d21ec..aaee31728f80e45b42d7443942290fe3967ec0e4 100644
--- a/third_party/WebKit/Source/bindings/core/v8/IDLTypes.h
+++ b/third_party/WebKit/Source/bindings/core/v8/IDLTypes.h
@@ -75,6 +75,36 @@ struct CORE_EXPORT IDLSequence final : public IDLBase {
       Vector<CppType>>::type;
 };
 
+// Record
+template <typename Key, typename Value>
+struct CORE_EXPORT IDLRecord final : public IDLBase {
+  static_assert(std::is_same<Key, IDLByteString>::value ||
+                    std::is_same<Key, IDLString>::value ||
+                    std::is_same<Key, IDLUSVString>::value,
+                "IDLRecord keys must be of a WebIDL string type");
+
+ private:
+  // Record keys are always strings, so we do not need to introspect them.
+  using ValueCppType = typename NativeValueTraits<Value>::ImplType;
+  using MaybeWrappedValueCppType = typename std::conditional<
+      WTF::IsGarbageCollectedType<ValueCppType>::value,
+      Member<ValueCppType>,
+      ValueCppType>::type;
+
+ public:
+  // Two kinds of types need HeapVector:
+  // 1. Oilpan types, which are wrapped by Member<>.
+  // 2. IDL unions and dictionaries, which are not Oilpan types themselves (and
+  //    are thus not wrapped by Member<>) but have a trace() method and can
+  //    contain Oilpan members. They both also happen to specialize V8TypeOf,
+  //    which we use to recognize them.
+  using ImplType = typename std::conditional<
+      std::is_same<MaybeWrappedValueCppType, Member<ValueCppType>>::value ||
+          std::is_class<typename V8TypeOf<ValueCppType>::Type>::value,
+      HeapVector<std::pair<String, MaybeWrappedValueCppType>>,
+      Vector<std::pair<String, ValueCppType>>>::type;
+};
+
 }  // namespace blink
 
 #endif  // IDLTypes_h