Pass in the prototype to CreateApiFunction rather than setting it on the result.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 2e92efb37b585a03d0831a7601d856487cfb2485..1b25ae3a4a01baef82b5f87cbd3bd59c66609e48 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -2134,9 +2134,10 @@ RUNTIME_FUNCTION(Runtime_RegExpCompile) {
 
 RUNTIME_FUNCTION(Runtime_CreateApiFunction) {
   HandleScope scope(isolate);
-  ASSERT(args.length() == 1);
+  ASSERT(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(FunctionTemplateInfo, data, 0);
-  return *isolate->factory()->CreateApiFunction(data);
+  CONVERT_ARG_HANDLE_CHECKED(Object, prototype, 1);
+  return *isolate->factory()->CreateApiFunction(data, prototype);
 }
 
 
@@ -2805,7 +2806,8 @@ static Handle<JSFunction> InstallBuiltin(Isolate* isolate,
   Handle<String> key = isolate->factory()->InternalizeUtf8String(name);
   Handle<Code> code(isolate->builtins()->builtin(builtin_name));
   Handle<JSFunction> optimized =
-      isolate->factory()->NewFunction(key,
+      isolate->factory()->NewFunction(MaybeHandle<Object>(),
+                                      key,
                                       JS_OBJECT_TYPE,
                                       JSObject::kHeaderSize,
                                       code,