Use dart.global instead of window in debugger.dart

lib/runtime/dart/_debugger.js

 dart_library.library('dart/_debugger', null, /* Imports */[
   'dart/_runtime',
   'dart/core'
 ], /* Lazy imports */[
 ], function(exports, dart, core) {
   'use strict';
   let dartx = dart.dartx;
   const skipDartConfig = dart.const(new core.Object());
   exports.maxIterableChildrenToDisplay = 50;
   dart.defineLazyProperties(exports, {
@@ skipping 514 matching lines @@
   dart.setSignature(HeritageClauseFormatter, {
     methods: () => ({
       accept: [core.bool, [dart.dynamic]],
       preview: [core.String, [dart.dynamic]],
       hasChildren: [core.bool, [dart.dynamic]],
       children: [core.List$(NameValuePair), [dart.dynamic]]
     })
   });
   function registerDevtoolsFormatter() {
     let formatters = [exports._devtoolsFormatter];
-    window.devtoolsFormatters = formatters;
+    dart.global.devtoolsFormatters = formatters;
   }
   dart.fn(registerDevtoolsFormatter);
   // Exports:
   exports.skipDartConfig = skipDartConfig;
   exports.getOwnPropertyNames = getOwnPropertyNames;
   exports.getOwnPropertySymbols = getOwnPropertySymbols;
   exports.JSNative = JSNative;
   exports.isRegularDartObject = isRegularDartObject;
   exports.getObjectTypeName = getObjectTypeName;
   exports.getTypeName = getTypeName;
@@ skipping 10 matching lines @@
   exports.DartFormatter = DartFormatter;
   exports.ObjectFormatter = ObjectFormatter;
   exports.FunctionFormatter = FunctionFormatter;
   exports.MapFormatter = MapFormatter;
   exports.IterableFormatter = IterableFormatter;
   exports.ClassMetadataFormatter = ClassMetadataFormatter;
   exports.MapEntryFormatter = MapEntryFormatter;
   exports.HeritageClauseFormatter = HeritageClauseFormatter;
   exports.registerDevtoolsFormatter = registerDevtoolsFormatter;
 });