Add NativeWeakMap to v8.h

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index eb7a8c399386091e8062fdfb6a690fb1cfa93b7d..aac6d84273fc67a060462acd5c6f1f5ecee8cb9e 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -1536,6 +1536,21 @@ class V8_EXPORT JSON {
 };
 
 
+/**
+ * A map whose keys are referenced weakly. It is similar to JavaScript WeakMap
+ * but can be created without entering a v8::Context and hence shouldn't
+ * escape to JavaScript.
+ */
+class V8_EXPORT NativeWeakMap : public Data {
+ public:
+  static Local<NativeWeakMap> New(Isolate* isolate);
+  void Set(Handle<Value> key, Handle<Value> value);
+  Local<Value> Get(Handle<Value> key);
+  bool Has(Handle<Value> key);
+  bool Delete(Handle<Value> key);
+};
+
+
 // --- Value ---