Fix handling of promises for title and description of pages in Quay

We were not correctly waiting for the `scope` on page to be filled before trying to calculate the title, and the logic for description was broken as well.

static/js/quay-run.ts

@@ -103,9 +103,10 @@ export function provideRun($rootScope: QuayRunScope,
 
   // Listen for route changes and update the title and description accordingly.
   $rootScope.$on('$routeChangeSuccess', async(event, current, previous) => {
-    $rootScope.title = metaService.getTitle(current) || defaultTitle;
-
+    const title = await metaService.getTitle(current);    
     const description = await metaService.getDescription(current);
+
+    $rootScope.title = title || defaultTitle;
     if ($rootScope.description != description) {
       $rootScope.description = description;
     }

static/js/services/meta-service.js

@@ -17,27 +17,32 @@ angular.module('quay').factory('MetaService', ['$interpolate', '$timeout', funct
     return inter(page.scope);
   };
 
-  metaService.getTitle = function(page) {
-    if (!page || !page.$$route) {
-      return null;
-    }
-
-    var route = page.$$route;
-    return interpolate(page, route && route.title);
-  };
-
-  metaService.getDescription = function(page) {
+  var interpolationPromise = function(page, fieldGetter) {    
     return new Promise(function(resolve, reject) {
       if (!page || !page.$$route) {
         resolve(null);
-      } else {
-        // Timeout needed because page.scope is undefined
-        $timeout(function() {
-          resolve(interpolate(page, page.$$route.description));
-        }, 10);
+        return;
       }
+
+      if (page.scope) {
+        resolve(interpolate(page, fieldGetter()));
+        return;
+      }
+
+      // Timeout needed because page.scope is initially undefined.
+      $timeout(function() {
+        resolve(interpolationPromise(page, fieldGetter));
+      }, 10);
     });
   };
 
+  metaService.getTitle = function(page) {
+    return interpolationPromise(page, () =>  page.$$route.title);
+  };
+
+  metaService.getDescription = function(page) {
+    return interpolationPromise(page, () =>  page.$$route.description);
+  };
+
   return metaService;
 }]);