[HTML Imports] Employ load/error events to stabilize polling-based tests.

LayoutTests/fast/dom/custom/registration-context-sharing.html

Index: LayoutTests/fast/dom/custom/registration-context-sharing.html
diff --git a/LayoutTests/fast/dom/custom/registration-context-sharing.html b/LayoutTests/fast/dom/custom/registration-context-sharing.html
index e843176c15da1a27b3b1989a8759e03fc7b9820c..a0d087c9f9336d55db532fcd9bb42a99f47dbd79 100644
--- a/LayoutTests/fast/dom/custom/registration-context-sharing.html
+++ b/LayoutTests/fast/dom/custom/registration-context-sharing.html
@@ -146,28 +146,18 @@ t.step(function () {
     link = documentA.createElement('link');
     link.rel = 'import';
     link.href = 'resources/empty-document.html';
+    link.onload = function() {
+        t.step(function () {

[dominicc (has gone to gerrit), 2013/09/10 23:06:30]

You can use step_func for this.

+            var documentB = link.import;
+            var tester = new TestRegistrationContextSharing(window,
+                                                            documentA, documentB);
+            tester.testRegistrationContextIsShared();
+            t.done();
+        });
+    };
     documentA.head.appendChild(link);
-
-    // FIXME: When imports raise the 'load' event, use that instead of
-    // polling.
-    waitForLinkToLoad();
 });
 
-function waitForLinkToLoad() {
-    if (!link.import) {
-        setTimeout(waitForLinkToLoad, 100);
-        return;
-    }
-
-    t.step(function () {
-        var documentB = link.import;
-        var tester = new TestRegistrationContextSharing(window,
-                                                        documentA, documentB);
-        tester.testRegistrationContextIsShared();
-        t.done();
-    });
-}
-
 })();
 
 </script>