Fix windows build.

vm/dart_api_impl.cc

 // 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.
 
 #include "include/dart_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 1696 matching lines @@
                                             intptr_t* length) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   if (latin1_array == NULL) {
     RETURN_NULL_ERROR(latin1_array);
   }
   if (length == NULL) {
     RETURN_NULL_ERROR(length);
   }
   const String& str_obj = Api::UnwrapStringHandle(isolate, str);
-  if (str_obj.IsNull() || !Dart_IsStringLatin1(str)) {
+  if (str_obj.IsNull() || !str_obj.IsOneByteString()) {
     RETURN_TYPE_ERROR(isolate, str, String);
   }
   intptr_t str_len = str_obj.Length();
   intptr_t copy_len = (str_len > *length) ? *length : str_len;
 
   // We have already asserted that the string object is a Latin-1 string
   // so we can copy the characters over using a simple loop.
   for (intptr_t i = 0; i < copy_len; i++) {
     latin1_array[i] = str_obj.CharAt(i);
   }
@@ skipping 2778 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success(isolate);
 }
 
 }  // namespace dart