Change IsolateNatives.computeThisScript to use captured value of document.currentScript.

dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

 // 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.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 560 matching lines @@
     //
     // We also copy over old values like the prototype, and the
     // isolateProperties themselves.
 
     // function(oldIsolate) {
     return js.fun('oldIsolate', [
       // var isolateProperties = oldIsolate.${namer.isolatePropertiesName};
       js['isolateProperties'].def(
                    js['oldIsolate'][namer.isolatePropertiesName]),
 
+      // isolateProperties.$currentScript =
+      //    (typeof document == "object") && (document.currentScript ||
+      //                 document.scripts[document.scripts.length - 1]);
+      js['isolateProperties'][r'$currentScript'].assign(
+          js['document'].typeof.equals(js.string('object')).binary(
+              '&&',
+              js['document']['currentScript'].binary(
+                  '||',
+                  js['document']['scripts'][
+                      js['document']['scripts']['length'] - 1]))),
+
       // var isolatePrototype = oldIsolate.prototype;
       js['isolatePrototype'].def(js['oldIsolate']['prototype']),
 
       // var str = "{\\n";
       js['str'].def(js.string(r'{\n')),
 
       // str += "var properties = $isolate.${namer.isolatePropertiesName};\\n";
       js['str'].update('+', js.string('var properties = '
                                       '$isolate.${namer.isolatePropertiesName};'
                                       r'\n')),
@@ skipping 2085 matching lines @@
 """;
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;