Improve memory usage of receiver type feedback.

src/stub-cache.h

Index: src/stub-cache.h
diff --git a/src/stub-cache.h b/src/stub-cache.h
index ffe4241ec14c2a35028f714839a236b676c447b4..a97a4cdab2a880d4158df59fc67095a194c630c6 100644
--- a/src/stub-cache.h
+++ b/src/stub-cache.h
@@ -46,8 +46,10 @@ namespace internal {
 // invalidate the cache whenever a prototype map is changed.  The stub
 // validates the map chain as in the mono-morphic case.
 
+class SmallMapList;
 class StubCache;
 
+
 class SCTableReference {
  public:
   Address address() const { return address_; }
@@ -294,7 +296,7 @@ class StubCache {
   void Clear();
 
   // Collect all maps that match the name and flags.
-  void CollectMatchingMaps(ZoneMapList* types,
+  void CollectMatchingMaps(SmallMapList* types,
                            String* name,
                            Code::Flags flags);