Use ParametrizedType instead of Type where appropriate. Expand ToCString of type related classes.

runtime/vm/raw_object_snapshot.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/visitor.h"
 
@@ skipping 126 matching lines @@
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawType* Type::ReadFrom(SnapshotReader* reader,
                         intptr_t object_id,
                         bool classes_serialized) {
   UNREACHABLE();  // Type is an abstract class.
-  return Type::null();
+  return NULL;
 }
 
 
 void RawType::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       bool serialize_classes) {
   UNREACHABLE();  // Type is an abstract class.
 }
 
 
@@ skipping 123 matching lines @@
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawTypeArguments* TypeArguments::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
                                           bool classes_serialized) {
   UNREACHABLE();  // TypeArguments is an abstract class.
-  return TypeArguments::null();
+  return TypeArray::null();
 }
 
 
 void RawTypeArguments::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                bool serialize_classes) {
   UNREACHABLE();  // TypeArguments is an abstract class.
 }
 
 
@@ skipping 1083 matching lines @@
   // Write out all the other fields.
   writer->Write<RawObject*>(ptr()->num_bracket_expressions_);
   writer->WriteObject(ptr()->pattern_);
   writer->Write<intptr_t>(ptr()->type_);
   writer->Write<intptr_t>(ptr()->flags_);
 
   // Do not write out the data part which is native.
 }
 
 }  // namespace dart