Never return a Dart_Handle on a dart::Class from the embedding API.

runtime/include/dart_api.h

 /*
  * 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.
  */
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 1156 matching lines @@
 /**
  * Gets the type of a Dart language object.
  *
  * \param instance Some Dart object.
  *
  * \return If no error occurs, the type is returned. Otherwise an
  *   error handle is returned.
  */
 DART_EXPORT Dart_Handle Dart_InstanceGetType(Dart_Handle instance);
 
-/**
- * TODO(asiva): Deprecate this method once all use cases have switched
- *              to using Dart_InstanceGetType
- * Gets the class for some Dart language object.
- *
- * \param instance Some Dart object.
- *
- * \return If no error occurs, the class is returned. Otherwise an
- *   error handle is returned.
- */
-DART_EXPORT Dart_Handle Dart_InstanceGetClass(Dart_Handle instance);
-
 
 /*
  * =============================
  * Numbers, Integers and Doubles
  * =============================
  */
 
 /**
  * Does this Integer fit into a 64-bit signed integer?
  *
@@ skipping 1084 matching lines @@
  *
  * \param object An object.
  * \param peer A value to store in the peer field.
  *
  * \return Returns an error if 'object' is a subtype of Null, num, or
  *   bool.
  */
 DART_EXPORT Dart_Handle Dart_SetPeer(Dart_Handle object, void* peer);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */