Add Instance::HashCode that matches hashCode.

runtime/vm/object.cc

 // Copyright (c) 2012, 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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 12840 matching lines @@
   for (intptr_t i = 0; i < param_values.Length(); i++) {
     param = param_values.At(i);
     args.SetAt(i + 1, param);
   }
   const Object& result =
       Object::Handle(DartEntry::InvokeFunction(eval_func, args));
   return result.raw();
 }
 
 
+RawObject* Instance::HashCode() const {
+  // TODO(koda): Optimize for all builtin classes and all classes
+  // that do not override hashCode.
+  return DartLibraryCalls::HashCode(*this);
+}
+
 
 bool Instance::CanonicalizeEquals(const Instance& other) const {
   if (this->raw() == other.raw()) {
     return true;  // "===".
   }
 
   if (other.IsNull() || (this->clazz() != other.clazz())) {
     return false;
   }
 
@@ skipping 6206 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart