[App Management] Uninstalling an app now behaves correctly.

This CL fixes the errors that stopped the main page from being shown
when an app was uninstalled. dom-switch now detaches it's child when
the app-permission-view is not being displayed.

Bug: 1001710
Change-Id: Iefb2e19a3a1aa70d69bbafa9c5b347a030f8fa0d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1799650
Commit-Queue: Jeevan Shikaram <jshikaram@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697449}

chrome/browser/resources/settings/chromeos/os_apps_page/app_management_page/app_permission_view.js

@@ -30,11 +30,13 @@ Polymer({
   },
 
   /**
+   * @param {App} app
+   * @return {?string}
    * @private
    */
   getSelectedRouteId_: function(app) {
     if (!app) {
-      return;
+      return null;
     }
 
     const selectedAppType = app.type;

chrome/browser/resources/settings/chromeos/os_apps_page/app_management_page/dom_switch.js

@@ -101,13 +101,19 @@ Polymer({
   },
 
   /**
-   * @param {string} newRouteId
+   * @param {?string} newRouteId
    */
   onRouteChanged_: function(newRouteId) {
     if (!this.instance_) {
       return;
     }
 
+    if (newRouteId === null) {
+      this.parentNode.removeChild(this.selectedChild_);
+      this.selectedChild_ = null;
+      return;
+    }
+
     const newSelectedChild = this.children_[newRouteId];
     assert(
         newSelectedChild,

chrome/browser/resources/settings/chromeos/os_apps_page/os_apps_page.js

@@ -44,6 +44,9 @@ Polymer({
    * @private
    */
   iconUrlFromId_: function(app) {
+    if (!app) {
+      return '';
+    }
     return app_management.util.getAppIcon(app);
   },
 

chrome/test/data/webui/settings/chromeos/app_management/dom_switch_test.js

@@ -44,6 +44,11 @@ suite('<app-management-dom-switch>', function() {
     domSwitch.route = '2';
     assertFalse(!!document.getElementById('child1'));
     assertTrue(!!document.getElementById('child2'));
+
+    // When no child is selected, the currently selected child is detached.
+    domSwitch.route = null;
+    assertFalse(!!document.getElementById('child1'));
+    assertFalse(!!document.getElementById('child2'));
   });
 
   test('binding to properties and paths works', function() {

chrome/test/data/webui/settings/chromeos/os_settings_browsertest.js

@@ -171,6 +171,27 @@ const OSSettingsAppManagementBrowserTest = class extends OSSettingsBrowserTest {
   }
 };
 
+// Text fixture for the app management dom switch element.
+// eslint-disable-next-line no-var
+var OSSettingsAppManagementDomSwitchTest =
+    class extends OSSettingsAppManagementBrowserTest {
+  /** @override */
+  get browsePreload() {
+    return super.browsePreload + 'app_management/dom_switch.html';
+  }
+
+  /** @override */
+  get extraLibraries() {
+    return super.extraLibraries.concat([
+      'app_management/dom_switch_test.js',
+    ]);
+  }
+};
+
+TEST_F('OSSettingsAppManagementDomSwitchTest', 'All', function() {
+  mocha.run();
+});
+
 // Test fixture for the app management settings page.
 // eslint-disable-next-line no-var
 var OSSettingsAppManagementPageTest =