Revert Dart_PropagateError until I can track down the problems in

runtime/vm/cpu.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 VM_CPU_H_
 #define VM_CPU_H_
 
 #include "vm/allocation.h"
 
 namespace dart {
 
 // Forward Declarations.
-class Error;
 class Instance;
+class UnhandledException;
 
 
 class CPU : public AllStatic {
  public:
   static void FlushICache(uword start, uword size);
   static void JumpToExceptionHandler(uword program_counter,
                                      uword stack_pointer,
                                      uword frame_pointer,
                                      const Instance& exception_object,
                                      const Instance& stacktrace_object);
-  static void JumpToErrorHandler(
+  static void JumpToUnhandledExceptionHandler(
       uword program_counter,
       uword stack_pointer,
       uword frame_pointer,
-      const Error& error);
+      const UnhandledException& unhandled_exception);
   static const char* Id();
 };
 
 }  // namespace dart
 
 #endif  // VM_CPU_H_