Use dart.global instead of window in debugger.dart
diff --git a/tool/input_sdk/private/debugger.dart b/tool/input_sdk/private/debugger.dart
index 2a8a877..c8d0285 100644
--- a/tool/input_sdk/private/debugger.dart
+++ b/tool/input_sdk/private/debugger.dart
@@ -536,5 +536,5 @@
 /// Dart Dev Compiler
 registerDevtoolsFormatter() {
   var formatters = [_devtoolsFormatter];
-  JS('', 'window.devtoolsFormatters = #', formatters);
+  JS('', 'dart.global.devtoolsFormatters = #', formatters);
 }