[TypeFeedbackVector] Delete unused DummySlot.

BUG=

Review-Url: https://codereview.chromium.org/2557333002
Cr-Commit-Position: refs/heads/master@{#41598}

src/type-feedback-vector.h

@@ -156,10 +156,6 @@ class TypeFeedbackMetadata : public FixedArray {
   static const int kSlotsCountIndex = 0;
   static const int kReservedIndexCount = 1;
 
-  static const int kNameTableEntrySize = 2;
-  static const int kNameTableSlotIndex = 0;
-  static const int kNameTableNameIndex = 1;
-
   // Returns number of feedback vector elements used by given slot kind.
   static inline int GetSlotSize(FeedbackVectorSlotKind kind);
 
@@ -283,10 +279,6 @@ class TypeFeedbackVector : public FixedArray {
   static const int kDummyKeyedStoreICSlot = 6;
 
   static Handle<TypeFeedbackVector> DummyVector(Isolate* isolate);
-  static FeedbackVectorSlot DummySlot(int dummyIndex) {
-    DCHECK(dummyIndex >= 0 && dummyIndex <= kDummyKeyedStoreICSlot);
-    return FeedbackVectorSlot(dummyIndex);
-  }
 
  private:
   void ClearSlotsImpl(SharedFunctionInfo* shared, bool force_clear);