[Signin iOS] Reload the Account Selector screen when identities change

ios/chrome/browser/ui/authentication/signin_account_selector_view_controller.mm

 // Copyright 2016 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.
 
 #include "ios/chrome/browser/ui/authentication/signin_account_selector_view_controller.h"
 
 #include <memory>
 
 #import "base/mac/foundation_util.h"
 #import "base/mac/scoped_nsobject.h"
@@ skipping 238 matching lines @@
   } else if (item.type == ItemTypeAddAccount) {
     [self.delegate accountSelectorControllerDidSelectAddAccount:self];
   }
 }
 
 #pragma mark - ChromeIdentityServiceObserver
 
 - (void)onIdentityListChanged {
   ChromeIdentity* selectedIdentity = [self selectedIdentity];
   [self loadModel];
+  [self.collectionView reloadData];
 
   // Reselect the identity.
   if (!selectedIdentity) {
     return;
   }
   NSArray* accountItems = [self.collectionViewModel
       itemsInSectionWithIdentifier:SectionIdentifierAccounts];
   for (CollectionViewAccountItem* accountItem in accountItems) {
     if ([accountItem.chromeIdentity.gaiaID
             isEqualToString:selectedIdentity.gaiaID]) {
@@ skipping 54 matching lines @@
       [self.collectionViewModel itemTypeForIndexPath:indexPath];
   return (itemType == ItemTypeTitle);
 }
 
 - (BOOL)collectionView:(nonnull UICollectionView*)collectionView
     shouldHideItemBackgroundAtIndexPath:(nonnull NSIndexPath*)indexPath {
   return YES;
 }
 
 @end