Add WeakMap to v8.h

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 1518 matching lines @@
    * Tries to parse the string |json_string| and returns it as value if
    * successful.
    *
    * \param json_string The string to parse.
    * \return The corresponding value if successfully parsed.
    */
   static Local<Value> Parse(Local<String> json_string);
 };
 
 
+/**
+ * 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 WeakKeyMap {
+ public:
+  static WeakKeyMap* New(Isolate* isolate);
+  ~WeakKeyMap();
+  void Set(Handle<Value> key, Handle<Value> value);
+  Local<Value> Get(Handle<Value> key);
+  bool Has(Handle<Value> key);
+  bool Delete(Handle<Value> key);
+
+ private:
+  WeakKeyMap(Isolate* isolate, Handle<Object> weak_map);
+
+  Isolate* isolate_;
+  UniquePersistent<Object> map_;
+
+  // Disallow copying and assigning.
+  WeakKeyMap(WeakKeyMap&);
+  void operator=(WeakKeyMap&);
+};
+
+
 // --- Value ---
 
 
 /**
  * The superclass of all JavaScript values and objects.
  */
 class V8_EXPORT Value : public Data {
  public:
   /**
    * Returns true if this value is the undefined value.  See ECMA-262
@@ skipping 5938 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_