[proxies] Teach ToPropertyDescriptor to deal with Proxies

src/property-descriptor.h

 // Copyright 2015 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.
 
 #ifndef V8_PROPERTY_DESCRIPTOR_H_
 #define V8_PROPERTY_DESCRIPTOR_H_
 
 
 #include "src/handles.h"
 #include "src/property-details.h"
@@ skipping 23 matching lines @@
   // ES6 6.2.4.2
   static bool IsDataDescriptor(PropertyDescriptor* desc) {
     return desc->has_value() || desc->has_writable();
   }
 
   // ES6 6.2.4.3
   static bool IsGenericDescriptor(PropertyDescriptor* desc) {
     return !IsAccessorDescriptor(desc) && !IsDataDescriptor(desc);
   }
 
+  // ES6 6.2.4.4
+  Handle<Object> ToObject(Isolate* isolate);
+
+  // ES6 6.2.4.5
+  static bool ToPropertyDescriptor(Isolate* isolate, Handle<Object> obj,
+                                   PropertyDescriptor* desc);
+
+  // ES6 6.2.4.6
+  static void CompletePropertyDescriptor(Isolate* isolate,
+                                         PropertyDescriptor* desc);
+
   bool is_empty() const {
     return !has_enumerable() && !has_configurable() && !has_writable() &&
            !has_value() && !has_get() && !has_set();
   }
 
   bool enumerable() const { return enumerable_; }
   void set_enumerable(bool enumerable) {
     enumerable_ = enumerable;
     has_enumerable_ = true;
   }
@@ skipping 28 matching lines @@
   Handle<Object> name() const { return name_; }
   void set_name(Handle<Object> name) { name_ = name; }
 
   PropertyAttributes ToAttributes() {
     return static_cast<PropertyAttributes>(
         (has_enumerable() && !enumerable() ? DONT_ENUM : NONE) |
         (has_configurable() && !configurable() ? DONT_DELETE : NONE) |
         (has_writable() && !writable() ? READ_ONLY : NONE));
   }
 
-  Handle<Object> ToObject(Isolate* isolate);
-
-  static bool ToPropertyDescriptor(Isolate* isolate, Handle<Object> obj,
-                                   PropertyDescriptor* desc);
-
  private:
   bool enumerable_ : 1;
   bool has_enumerable_ : 1;
   bool configurable_ : 1;
   bool has_configurable_ : 1;
   bool writable_ : 1;
   bool has_writable_ : 1;
   Handle<Object> value_;
   Handle<Object> get_;
   Handle<Object> set_;
   Handle<Object> name_;
 
   // Some compilers (Xcode 5.1, ARM GCC 4.9) insist on having a copy
   // constructor for std::vector<PropertyDescriptor>, so we can't
   // DISALLOW_COPY_AND_ASSIGN(PropertyDescriptor); here.
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PROPERTY_DESCRIPTOR_H_