| Index: runtime/lib/isolate.cc
 | 
| diff --git a/runtime/lib/isolate.cc b/runtime/lib/isolate.cc
 | 
| index 4e1fce8dc4e40f1138ec86c70e6ef6527165c436..f6d248a145b460d078e65ba91c3fe47df2506a80 100644
 | 
| --- a/runtime/lib/isolate.cc
 | 
| +++ b/runtime/lib/isolate.cc
 | 
| @@ -298,6 +298,7 @@ static const char* CanonicalizeUri(Thread* thread,
 | 
|    Isolate* isolate = thread->isolate();
 | 
|    Dart_LibraryTagHandler handler = isolate->library_tag_handler();
 | 
|    if (handler != NULL) {
 | 
| +    TransitionVMToNative transition(thread);
 | 
|      Dart_EnterScope();
 | 
|      Dart_Handle handle = handler(Dart_kCanonicalizeUrl,
 | 
|                                   Api::NewHandle(thread, library.raw()),
 | 
| 
 |