Remove unused descriptor slack from strict functions to avoid breaking initial map descriptor shari…

src/bootstrapper.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/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/code-stubs.h"
 #include "src/extensions/externalize-string-extension.h"
@@ skipping 579 matching lines @@
 
   // ES6 draft 03-17-2015, section 8.2.2 step 12
   AddRestrictedFunctionProperties(empty_function_map);
 
   return empty_function;
 }
 
 
 void Genesis::SetStrictFunctionInstanceDescriptor(Handle<Map> map,
                                                   FunctionMode function_mode) {
-  int size = IsFunctionModeWithPrototype(function_mode) ? 5 : 4;
+  int size = IsFunctionModeWithPrototype(function_mode) ? 3 : 2;
   Map::EnsureDescriptorSlack(map, size);
 
   PropertyAttributes rw_attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE);
   PropertyAttributes ro_attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY);
   PropertyAttributes roc_attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY);
 
   if (function_mode == BOUND_FUNCTION) {
@@ skipping 2666 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8