Add asserts to ensure that we:

src/x64/code-stubs-x64.h

 // Copyright 2011 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 395 matching lines @@
       Register r0);
 
   static void GeneratePositiveLookup(MacroAssembler* masm,
                                      Label* miss,
                                      Label* done,
                                      Register elements,
                                      Register name,
                                      Register r0,
                                      Register r1);
 
+  virtual bool SometimesSetsUpAFrame() { return false; }
+
  private:
   static const int kInlinedProbes = 4;
   static const int kTotalProbes = 20;
 
   static const int kCapacityOffset =
       StringDictionary::kHeaderSize +
       StringDictionary::kCapacityIndex * kPointerSize;
 
   static const int kElementsStartOffset =
       StringDictionary::kHeaderSize +
       StringDictionary::kElementsStartIndex * kPointerSize;
 
-  Major MajorKey() { return StringDictionaryNegativeLookup; }
+  Major MajorKey() { return StringDictionaryLookup; }
 
   int MinorKey() {
     return DictionaryBits::encode(dictionary_.code()) |
         ResultBits::encode(result_.code()) |
         IndexBits::encode(index_.code()) |
         LookupModeBits::encode(mode_);
   }
 
   class DictionaryBits: public BitField<int, 0, 4> {};
   class ResultBits: public BitField<int, 4, 4> {};
   class IndexBits: public BitField<int, 8, 4> {};
   class LookupModeBits: public BitField<LookupMode, 12, 1> {};
 
   Register dictionary_;
   Register result_;
   Register index_;
   LookupMode mode_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODE_STUBS_X64_H_