Introduce basic type feedback for for-in statements to avoid deopts.

src/type-info.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 210 matching lines @@
 class Call;
 class CallNew;
 class CaseClause;
 class CompareOperation;
 class CompilationInfo;
 class CountOperation;
 class Expression;
 class Property;
 class SmallMapList;
 class UnaryOperation;
+class ForInStatement;
 
 
 class TypeFeedbackOracle BASE_EMBEDDED {
  public:
   TypeFeedbackOracle(Handle<Code> code,
                      Handle<Context> global_context,
                      Isolate* isolate);
 
   bool LoadIsMonomorphicNormal(Property* expr);
   bool LoadIsMegamorphicWithTypeInfo(Property* expr);
   bool StoreIsMonomorphicNormal(Expression* expr);
   bool StoreIsMegamorphicWithTypeInfo(Expression* expr);
   bool CallIsMonomorphic(Call* expr);
   bool CallNewIsMonomorphic(CallNew* expr);
 
+  bool IsForInFastCase(ForInStatement* expr);
+
   Handle<Map> LoadMonomorphicReceiverType(Property* expr);
   Handle<Map> StoreMonomorphicReceiverType(Expression* expr);
 
   void LoadReceiverTypes(Property* expr,
                          Handle<String> name,
                          SmallMapList* types);
   void StoreReceiverTypes(Assignment* expr,
                           Handle<String> name,
                           SmallMapList* types);
   void CallReceiverTypes(Call* expr,
@@ skipping 53 matching lines @@
   Handle<Context> global_context_;
   Isolate* isolate_;
   Handle<UnseededNumberDictionary> dictionary_;
 
   DISALLOW_COPY_AND_ASSIGN(TypeFeedbackOracle);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_TYPE_INFO_H_