Make sure Bigint._digits is always a Uint32List (instead of sometimes null).

runtime/vm/dart_api_message.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_DART_API_MESSAGE_H_
 #define VM_DART_API_MESSAGE_H_
 
 #include "include/dart_native_api.h"
 #include "vm/dart_api_state.h"
 #include "vm/snapshot.h"
@@ skipping 118 matching lines @@
 
   // Allocation of the structures for the decoded message happens
   // either in the supplied zone or using the supplied allocation
   // function.
   ReAlloc alloc_;
   ApiGrowableArray<BackRefNode*> backward_references_;
   Dart_CObject** vm_symbol_references_;
 
   Dart_CObject type_arguments_marker;
   Dart_CObject dynamic_type_marker;
+  static _Dart_CObject* singleton_uint32_typed_data_;
 };
 
 
 class ApiMessageWriter : public BaseWriter {
  public:
   static const intptr_t kInitialSize = 512;
   ApiMessageWriter(uint8_t** buffer, ReAlloc alloc)
       : BaseWriter(buffer, alloc, kInitialSize),
         object_id_(0), forward_list_(NULL),
         forward_list_length_(0), forward_id_(0) {
@@ skipping 37 matching lines @@
   Dart_CObject** forward_list_;
   intptr_t forward_list_length_;
   intptr_t forward_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ApiMessageWriter);
 };
 
 }  // namespace dart
 
 #endif  // VM_DART_API_MESSAGE_H_