Track up to 5 stable maps as field type.

src/types.h

 // 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.
 
 #ifndef V8_TYPES_H_
 #define V8_TYPES_H_
 
 #include "handles.h"
 
 namespace v8 {
@@ skipping 303 matching lines @@
   static TypeHandle NowOf(i::Object* value, Region* region);
   static TypeHandle NowOf(i::Handle<i::Object> value, Region* region) {
     return NowOf(*value, region);
   }
   bool NowIs(TypeImpl* that);
   template<class TypeHandle>
   bool NowIs(TypeHandle that)  { return this->NowIs(*that); }
   inline bool NowContains(i::Object* val);
   bool NowContains(i::Handle<i::Object> val) { return this->NowContains(*val); }
 
+  bool NowStable();
+
   bool IsClass() { return Config::is_class(this); }
   bool IsConstant() { return Config::is_constant(this); }
   bool IsArray() { return Config::is_struct(this, StructuralType::kArrayTag); }
   bool IsFunction() {
     return Config::is_struct(this, StructuralType::kFunctionTag);
   }
 
   ClassType* AsClass() { return ClassType::cast(this); }
   ConstantType* AsConstant() { return ConstantType::cast(this); }
   ArrayType* AsArray() { return ArrayType::cast(this); }
@@ skipping 387 matching lines @@
   bool Narrows(BoundsImpl that) {
     return that.lower->Is(this->lower) && this->upper->Is(that.upper);
   }
 };
 
 typedef BoundsImpl<ZoneTypeConfig> Bounds;
 
 } }  // namespace v8::internal
 
 #endif  // V8_TYPES_H_