Remove NullPointerException.

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"
 
@@ skipping 38 matching lines @@
 
   enum ExceptionType {
     kNone,
     kRange,
     kArgument,
     kNoSuchMethod,
     kFormat,
     kStackOverflow,
     kOutOfMemory,
     kInternalError,
-    kNullPointer,
+    kNullThrown,
     kIllegalJSRegExp,
-    kArgumentError,
     kIsolateSpawn
   };
 
   static void ThrowByType(ExceptionType type,
                           const GrowableArray<const Object*>& arguments);
   // Returns a RawInstance if the exception is successfully created,
   // otherwise returns a RawError.
   static RawObject* Create(ExceptionType type,
                            const GrowableArray<const Object*>& arguments);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Exceptions);
 };
 
 }  // namespace dart
 
 #endif  // VM_EXCEPTIONS_H_