Add the ability to change the working directory

runtime/bin/dartutils.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 "bin/dartutils.h"
 
 #include "bin/extensions.h"
 #include "bin/directory.h"
 #include "bin/file.h"
 #include "bin/io_buffer.h"
@@ skipping 548 matching lines @@
   args[1] = os_error;
   return Dart_New(clazz, Dart_Null(), 2, args);
 }
 
 
 Dart_Handle DartUtils::NewDartExceptionWithMessage(const char* library_url,
                                                    const char* exception_name,
                                                    const char* message) {
   // Create a Dart Exception object with a message.
   Dart_Handle clazz = GetDartClass(library_url, exception_name);
-  Dart_Handle args[1];
-  args[0] = NewString(message);
-  return Dart_New(clazz, Dart_Null(), 1, args);
+  if (message != NULL) {
+    Dart_Handle args[1];
+    args[0] = NewString(message);
+    return Dart_New(clazz, Dart_Null(), 1, args);
+  } else {
+    return Dart_New(clazz, Dart_Null(), 0, NULL);
+  }
 }
 
 
 Dart_Handle DartUtils::NewDartArgumentError(const char* message) {
   return NewDartExceptionWithMessage(kCoreLibURL,
                                      "ArgumentError",
                                      message);
 }
 
 
@@ skipping 166 matching lines @@
       new CObjectString(CObject::NewString(os_error->message()));
   CObjectArray* result = new CObjectArray(CObject::NewArray(3));
   result->SetAt(0, new CObjectInt32(CObject::NewInt32(kOSError)));
   result->SetAt(1, new CObjectInt32(CObject::NewInt32(os_error->code())));
   result->SetAt(2, error_message);
   return result;
 }
 
 }  // namespace bin
 }  // namespace dart