[compiler] Drop the CompareNilIC.

src/ic/ic.h

Index: src/ic/ic.h
diff --git a/src/ic/ic.h b/src/ic/ic.h
index 2ce182b76e4ede86d11ca9df82399eff333f8492..4f07e867d1518298a465e35992f26bafd5eef4b1 100644
--- a/src/ic/ic.h
+++ b/src/ic/ic.h
@@ -624,18 +624,6 @@ class CompareIC : public IC {
 };
 
 
-class CompareNilIC : public IC {
- public:
-  explicit CompareNilIC(Isolate* isolate) : IC(EXTRA_CALL_FRAME, isolate) {}
-
-  Handle<Object> CompareNil(Handle<Object> object);
-
-  static Handle<Code> GetUninitialized();
-
-  static void Clear(Address address, Code* target, Address constant_pool);
-};
-
-
 class ToBooleanIC : public IC {
  public:
   explicit ToBooleanIC(Isolate* isolate) : IC(EXTRA_CALL_FRAME, isolate) {}