Ignore irrelevant link tags in custom HTML.

lib/dart.js

 // Copyright (c) 2015, 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.
 
 // This script runs in HTML files and loads the corresponding test scripts for
 // either Dartium or a JS browser. It's used by "pub serve" and user-authored
 // HTML files; when running without "pub serve", the default HTML file manually
 // chooses between serving a Dart or JS script tag.
 window.onload = function() {
 
@@ skipping 12 matching lines @@
 var name = window.location.href.replace(/.*\//, '').replace(/#.*/, '');
 
 // Find <link rel="x-dart-test">.
 var links = document.getElementsByTagName("link");
 var testLinks = [];
 var length = links.length;
 for (var i = 0; i < length; ++i) {
   if (links[i].rel == "x-dart-test") testLinks.push(links[i]);
 }
 
-if (links.length != 1) {
+if (testLinks.length != 1) {
   sendLoadException(
       'Expected exactly 1 <link rel="x-dart-test"> in ' + name + ', found ' +
-          links.length + '.');
+          testLinks.length + '.');
   return;
 }
 
-var link = links[0];
+var link = testLinks[0];
 
 if (link.href == '') {
   sendLoadException(
       'Expected <link rel="x-dart-test"> in ' + name + ' to have an "href" ' +
           'attribute.');
   return;
 }
 
 var script = document.createElement('script');
 
 // Load the compiled JS for a normal browser, and the Dart code for Dartium.
 if (navigator.userAgent.indexOf('(Dart)') === -1) {
   script.src = link.href + '.browser_test.dart.js';
 } else {
   script.src = link.href + '.browser_test.dart';
   script.type = 'application/dart';
 }
 
 script.onerror = function(event) {
   var message = "Failed to load script at " + script.src +
       (event.message ? ": " + event.message : ".");
   sendLoadException(message);
 }
 
 var parent = link.parentNode;
 document.currentScript = script;
 parent.replaceChild(script, link);
 
 };