[runtime] Support Proxy setPrototypeOf trap

src/objects.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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 1012 matching lines @@
   // a keyed store is of the form a[expression] = foo.
   enum StoreFromKeyed {
     MAY_BE_STORE_FROM_KEYED,
     CERTAINLY_NOT_STORE_FROM_KEYED
   };
 
   enum ShouldThrow { THROW_ON_ERROR, DONT_THROW };
 
 #define RETURN_FAILURE(isolate, should_throw, call) \
   do {                                              \
-    if ((should_throw) == DONT_THROW) {             \
+    if ((should_throw) == Object::DONT_THROW) {     \
       return Just(false);                           \
     } else {                                        \
       isolate->Throw(*isolate->factory()->call);    \
       return Nothing<bool>();                       \
     }                                               \
   } while (false)
 
 #define MAYBE_RETURN(call, value)         \
   do {                                    \
     if ((call).IsNothing()) return value; \
@@ skipping 8527 matching lines @@
   DECL_ACCESSORS(handler, Object)
   // [target]: The target property.
   DECL_ACCESSORS(target, Object)
   // [hash]: The hash code property (undefined if not initialized yet).
   DECL_ACCESSORS(hash, Object)
 
   inline bool has_handler();
 
   DECLARE_CAST(JSProxy)
 
-  static MaybeHandle<Object> GetPrototype(Handle<JSProxy> receiver);
+  // Proxy Traps:
+  static MaybeHandle<Object> GetPrototype(Handle<JSProxy> proxy);
+  static Maybe<bool> SetPrototype(Handle<JSProxy> proxy, Handle<Object> value,
+                                  bool from_javascript,
+                                  ShouldThrow should_throw);

[neis, 2015/11/16 19:09:54]

Shouldn't they be marked as MUST_USE_RESULT?

 
   MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithHandler(
       Handle<JSProxy> proxy,
       Handle<Object> receiver,
       Handle<Name> name);
 
   // If the handler defines an accessor property with a setter, invoke it.
   // If it defines an accessor property without a setter, or a data property
   // that is read-only, fail.  In all these cases set '*done' to true.
   // Otherwise set it to false, in which case the return value is not
@@ skipping 1182 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_