Resubmit reverted r17962, but, for now, only report error about unfinalized

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
===================================================================
--- runtime/vm/raw_object.h	(revision 18032)
+++ runtime/vm/raw_object.h	(working copy)
@@ -455,6 +455,8 @@
   friend class Object;
   friend class RawInstance;
   friend class RawInstructions;
+  friend class RawType;  // TODO(regis): To temporarily print unfinalized types.
+  friend class RawTypeParameter;  // To temporarily print unfinalized types.
   friend class SnapshotReader;
 };
 
@@ -471,6 +473,8 @@
     return reinterpret_cast<RawObject**>(&ptr()->ident_);
   }
   intptr_t token_pos_;
+
+  friend class RawType;  // TODO(regis): To temporarily print unfinalized types.
 };