Some cleanup and be more conservative when guessing cids: use only current leaf classes; otherwise …

runtime/vm/cha.cc

Index: runtime/vm/cha.cc
diff --git a/runtime/vm/cha.cc b/runtime/vm/cha.cc
index 4b005049772d29cebab6280f7674c5d6b6cdeb54..a2f50a3449254ce917ddf5075380858e214deb29 100644
--- a/runtime/vm/cha.cc
+++ b/runtime/vm/cha.cc
@@ -36,12 +36,12 @@ bool CHA::HasSubclasses(const Class& cls) {
     return true;
   }
   const GrowableObjectArray& direct_subclasses =
-      GrowableObjectArray::Handle(thread_->zone(), cls.direct_subclasses());
+      GrowableObjectArray::Handle(cls.direct_subclasses());
   return !direct_subclasses.IsNull() && (direct_subclasses.Length() > 0);
 }
 
 
-bool CHA::HasSubclasses(intptr_t cid) {
+bool CHA::HasSubclasses(intptr_t cid) const {
   const ClassTable& class_table = *thread_->isolate()->class_table();
   Class& cls = Class::Handle(thread_->zone(), class_table.At(cid));
   return HasSubclasses(cls);