Use a simpler and more reliable way to access the global scope in tes…

…tharness.js.

In particular, this should work in JS shells.

resources/testharness.js

@@ -13,7 +13,7 @@ policies and contribution forms [3].
 /* Documentation: http://web-platform-tests.org/writing-tests/testharness-api.html
  * (../docs/_writing-tests/testharness-api.md) */
 
-(function ()
+(function (global_scope)
 {
     var debug = false;
     // default timeout is 10 seconds, test can override if needed
@@ -48,9 +48,6 @@ policies and contribution forms [3].
      *
      *   // Should return the test harness timeout duration in milliseconds.
      *   float test_timeout();
-     *
-     *   // Should return the global scope object.
-     *   object global_scope();
      * };
      */
 
@@ -248,10 +245,6 @@ policies and contribution forms [3].
         return settings.harness_timeout.normal;
     };
 
-    WindowTestEnvironment.prototype.global_scope = function() {
-        return window;
-    };
-
     /*
      * Base TestEnvironment implementation for a generic web worker.
      *
@@ -344,10 +337,6 @@ policies and contribution forms [3].
         return null;
     };
 
-    WorkerTestEnvironment.prototype.global_scope = function() {
-        return self;
-    };
-
     /*
      * Dedicated web workers.
      * https://html.spec.whatwg.org/multipage/workers.html#dedicatedworkerglobalscope
@@ -463,23 +452,23 @@ policies and contribution forms [3].
     };
 
     function create_test_environment() {
-        if ('document' in self) {
+        if ('document' in global_scope) {
             return new WindowTestEnvironment();
         }
-        if ('DedicatedWorkerGlobalScope' in self &&
-            self instanceof DedicatedWorkerGlobalScope) {
+        if ('DedicatedWorkerGlobalScope' in global_scope &&
+            global_scope instanceof DedicatedWorkerGlobalScope) {
             return new DedicatedWorkerTestEnvironment();
         }
-        if ('SharedWorkerGlobalScope' in self &&
-            self instanceof SharedWorkerGlobalScope) {
+        if ('SharedWorkerGlobalScope' in global_scope &&
+            global_scope instanceof SharedWorkerGlobalScope) {
             return new SharedWorkerTestEnvironment();
         }
-        if ('ServiceWorkerGlobalScope' in self &&
-            self instanceof ServiceWorkerGlobalScope) {
+        if ('ServiceWorkerGlobalScope' in global_scope &&
+            global_scope instanceof ServiceWorkerGlobalScope) {
             return new ServiceWorkerTestEnvironment();
         }
-        if ('WorkerGlobalScope' in self &&
-            self instanceof WorkerGlobalScope) {
+        if ('WorkerGlobalScope' in global_scope &&
+            global_scope instanceof WorkerGlobalScope) {
             return new DedicatedWorkerTestEnvironment();
         }
 
@@ -489,13 +478,13 @@ policies and contribution forms [3].
     var test_environment = create_test_environment();
 
     function is_shared_worker(worker) {
-        return 'SharedWorker' in self && worker instanceof SharedWorker;
+        return 'SharedWorker' in global_scope && worker instanceof SharedWorker;
     }
 
     function is_service_worker(worker) {
         // The worker object may be from another execution context,
         // so do not use instanceof here.
-        return 'ServiceWorker' in self &&
+        return 'ServiceWorker' in global_scope &&
             Object.prototype.toString.call(worker) == '[object ServiceWorker]';
     }
 
@@ -2824,7 +2813,7 @@ policies and contribution forms [3].
     function expose(object, name)
     {
         var components = name.split(".");
-        var target = test_environment.global_scope();
+        var target = global_scope;
         for (var i = 0; i < components.length - 1; i++) {
             if (!(components[i] in target)) {
                 target[components[i]] = {};
@@ -2846,7 +2835,7 @@ policies and contribution forms [3].
     /** Returns the 'src' URL of the first <script> tag in the page to include the file 'testharness.js'. */
     function get_script_url()
     {
-        if (!('document' in self)) {
+        if (!('document' in global_scope)) {
             return undefined;
         }
 
@@ -2954,5 +2943,5 @@ policies and contribution forms [3].
 
     test_environment.on_tests_ready();
 
-})();
+})(this);
 // vim: set expandtab shiftwidth=4 tabstop=4: