PDFExtensionTest: Stop using chrome:// URL to load mock-interactions.js

chrome/test/data/pdf/toolbar_manager_test.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A cut-down version of MockInteractions.move, which is not exposed
 // publicly.
 function getMouseMoveEvents(fromX, fromY, toX, toY, steps) {
   var dx = Math.round((toX - fromX) / steps);
   var dy = Math.round((toY - fromY) / steps);
   var events = [];
@@ skipping 176 matching lines @@
     chrome.test.assertTrue(toolbar.opened,
                            "toolbars stay open after tap near toolbars");
     mockWindow.runTimeout();
     chrome.test.assertTrue(toolbar.opened,
                            "tap near toolbars prevents auto close");
 
     chrome.test.succeed();
   }
 ];
 
-importTestHelpers().then(function() {
-  chrome.test.runTests(tests);
-});
+chrome.test.runTests(tests);