Fast app reinstall: Encode the data URI contents

This is required after the change in
https://chromium-review.googlesource.com/c/1297172

Bug: 900793
Change-Id: I6f21fefc9d24f7209e7cfc8569c009c27a90c236
Reviewed-on: https://chromium-review.googlesource.com/c/1315968Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Yue Cen <rsgingerrs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606203}

chrome/browser/resources/chromeos/login/screen_recommend_apps.js

@@ -78,7 +78,8 @@ login.createScreen('RecommendAppsScreen', 'recommend-apps', function() {
 
     setWebview: function(contents) {
       var appListView = this.getElement_('app-list-view');
-      appListView.src = 'data:text/html;charset=utf-8,' + contents;
+      appListView.src =
+          'data:text/html;charset=utf-8,' + encodeURIComponent(contents);
     },
 
     /**