testing_app: Rebuild runners (#995)

testing_app/web/index.html

@@ -10,8 +10,11 @@
 
     For more details:
     * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
+
+    This is a placeholder for base href that will be replaced by the value of
+    the `--base-href` argument provided to `flutter build`.
   -->
-  <base href="/">
+  <base href="$FLUTTER_BASE_HREF">
 
   <meta charset="UTF-8">
   <meta content="IE=Edge" http-equiv="X-UA-Compatible">
@@ -23,6 +26,9 @@
   <meta name="apple-mobile-web-app-title" content="testing_app">
   <link rel="apple-touch-icon" href="icons/Icon-192.png">
 
+  <!-- Favicon -->
+  <link rel="icon" type="image/png" href="favicon.png"/>
+
   <title>testing_app</title>
   <link rel="manifest" href="manifest.json">
 </head>
@@ -64,7 +70,7 @@
             if (!reg.active && (reg.installing || reg.waiting)) {
               // No active web worker and we have installed or are installing
               // one for the first time. Simply wait for it to activate.
-              waitForActivation(reg.installing ?? reg.waiting);
+              waitForActivation(reg.installing || reg.waiting);
             } else if (!reg.active.scriptURL.endsWith(serviceWorkerVersion)) {
               // When the app updates the serviceWorkerVersion changes, so we
               // need to ask the service worker to update.