Turn on Polymer TodoMVC tests on Dart buildbots

pkg/unittest/lib/test_controller.js

Index: pkg/unittest/lib/test_controller.js
diff --git a/pkg/unittest/lib/test_controller.js b/pkg/unittest/lib/test_controller.js
index 439b7033aea8b4d4a097ec61f907ad8848ba0cc4..fc8db1611a5ae5b792cff8cfba3b2e6357dd3ede 100644
--- a/pkg/unittest/lib/test_controller.js
+++ b/pkg/unittest/lib/test_controller.js
@@ -23,7 +23,8 @@ window.onerror = function (message, url, lineNumber) {
   window.postMessage('unittest-suite-external-error', '*');
 };
 
-if (navigator.webkitStartDart) {
+// Start Dartium/content_shell, unless we are waiting for HTML Imports to load.
+if (navigator.webkitStartDart && !window.HTMLImports) {

[kustermann, 2013/08/30 15:34:43]

Please elaborate here a bit (in particular mention the interaction with polymer)
-- as time goes by these kind of things can easily be forgotten.

[Jennifer Messerly, 2013/08/30 18:07:36]

Attempted to clarify:

// Start Dartium/content_shell, unless we are waiting for HTML Imports to load.
// HTML Imports allows a document to link to other HTMLs documents via
// <link rel=import>. It also allows for those other documents to contain
// <script> tags, which must be run before scripts on the main page.
// We have package:html_import to polyfill this feature, and it will handle
// starting Dartium/content_shell in that case. HTML Imports is used by Polymer,
// but it could be used by itself too. See the specification:
// https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/imports/index.html

   navigator.webkitStartDart();
 }