Implement type cast in the VM.

runtime/vm/exceptions.h

 // 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.
 
 #ifndef VM_EXCEPTIONS_H_
 #define VM_EXCEPTIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 
 namespace dart {
 
 // Forward declarations.
 class Class;
 class DartFrameIterator;
 class Error;
 class Instance;
 class Object;
 class RawInstance;
 class RawScript;
 class RawObject;
 class Script;
 class String;
 
 class Exceptions : AllStatic {
  public:
+  static const char* kCastExceptionDstName;
+
   static void Throw(const Instance& exception);
   static void ReThrow(const Instance& exception, const Instance& stacktrace);
   static void PropagateError(const Object& obj);
 
   // Helpers to create and throw errors.
   static RawScript* GetCallerScript(DartFrameIterator* iterator);
   static RawInstance* NewInstance(const char* class_name);
   static void SetField(const Instance& instance,
                        const Class& cls,
                        const char* field_name,
@@ skipping 31 matching lines @@
   static RawObject* Create(ExceptionType type,
                            const GrowableArray<const Object*>& arguments);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Exceptions);
 };
 
 }  // namespace dart
 
 #endif  // VM_EXCEPTIONS_H_