Reintroduced dictionary that can use objects as keys.

src/handles.h

Index: src/handles.h
diff --git a/src/handles.h b/src/handles.h
index 13c6dd67f71e4aca1c7b59e6057f143a29347fd3..9bb3b1f1d5cac7fa2e7e13e896b41e557e07c0eb 100644
--- a/src/handles.h
+++ b/src/handles.h
@@ -264,9 +264,13 @@ Handle<Object> GetPrototype(Handle<Object> obj);
 Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value);
 
 // Return the object's hidden properties object. If the object has no hidden
-// properties and create_if_needed is true, then a new hidden property object
-// will be allocated. Otherwise the Heap::undefined_value is returned.
-Handle<Object> GetHiddenProperties(Handle<JSObject> obj, bool create_if_needed);
+// properties and HiddenPropertiesFlag::ALLOW_CREATION is passed, then a new
+// hidden property object will be allocated. Otherwise Heap::undefined_value
+// is returned.
+Handle<Object> GetHiddenProperties(Handle<JSObject> obj,
+                                   JSObject::HiddenPropertiesFlag flag);
+
+int GetIdentityHash(Handle<JSObject> obj);
 
 Handle<Object> DeleteElement(Handle<JSObject> obj, uint32_t index);
 Handle<Object> DeleteProperty(Handle<JSObject> obj, Handle<String> prop);
@@ -343,6 +347,10 @@ Handle<Object> SetPrototype(Handle<JSFunction> function,
 
 Handle<Object> PreventExtensions(Handle<JSObject> object);
 
+Handle<ObjectHashTable> PutIntoObjectHashTable(Handle<ObjectHashTable> table,
+                                               Handle<JSObject> key,
+                                               Handle<Object> value);
+
 // Does lazy compilation of the given function. Returns true on success and
 // false if the compilation resulted in a stack overflow.
 enum ClearExceptionFlag { KEEP_EXCEPTION, CLEAR_EXCEPTION };