[proxies] Make Object.prototype.isPrototypeOf work with proxies.

src/runtime/runtime-object.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 1520 matching lines @@
   Handle<Object> prototype;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, prototype,
       Object::GetProperty(callable, isolate->factory()->prototype_string()));
   if (!prototype->IsJSReceiver()) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate,
         NewTypeError(MessageTemplate::kInstanceofNonobjectProto, prototype));
   }
   // Return whether or not {prototype} is in the prototype chain of {object}.
-  return isolate->heap()->ToBoolean(
-      object->HasInPrototypeChain(isolate, *prototype));
+  Maybe<bool> result = Object::HasInPrototypeChain(isolate, object, prototype);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  return isolate->heap()->ToBoolean(result.FromJust());
 }
 
 
 RUNTIME_FUNCTION(Runtime_HasInPrototypeChain) {
-  SealHandleScope scope(isolate);
+  HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
-  CONVERT_ARG_CHECKED(Object, object, 0);
-  CONVERT_ARG_CHECKED(Object, prototype, 1);
-  return isolate->heap()->ToBoolean(
-      object->HasInPrototypeChain(isolate, prototype));
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, prototype, 1);
+  Maybe<bool> result = Object::HasInPrototypeChain(isolate, object, prototype);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  return isolate->heap()->ToBoolean(result.FromJust());
 }
 
 
 // ES6 section 7.4.7 CreateIterResultObject ( value, done )
 RUNTIME_FUNCTION(Runtime_CreateIterResultObject) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, done, 1);
   return *isolate->factory()->NewJSIteratorResult(value, done);
@@ skipping 20 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_ObjectDefineProperties) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(Object, o, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, properties, 1);
   return JSReceiver::DefineProperties(isolate, o, properties);
 }
 }  // namespace internal
 }  // namespace v8