[iOS][Signin] Fixing workflow when starting the sign-in in Recent Tabs

The SigninPromoViewMediator should not be deallocated until the sign-in
is finished. When the user clicks on "Continue as ...", the sign-in
is done as soon as the sign-in dialogs arrives.

RecentTabsTableViewController should not be updated as long as the
sign-in started by SigninPromoViewMediator is in progress.

Once the sign-in is done, the RecentTabsTableViewController can be
reloaded.

cronet;master.tryserver.chromium.mac:ios-simulator-full-configs

Bug: 798443
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I4a0937986e236473a7c0314c056cf437a0088c36
Reviewed-on: https://chromium-review.googlesource.com/846995
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526678}

ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_table_coordinator.mm

@@ -251,4 +251,9 @@
   [self.delegate updateNtpBarShadowForPanelController:self];
 }
 
+- (void)refreshSessionsViewRecentTabsTableViewController:
+    (RecentTabsTableViewController*)controller {
+  [self refreshSessionsView];
+}
+
 @end

ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_table_view_controller.h

@@ -29,6 +29,10 @@ extern NSString* const kRecentTabsTableViewControllerAccessibilityIdentifier;
 @protocol RecentTabsTableViewControllerDelegate<NSObject>
 // Tells the delegate when the table view content scrolled or changed size.
 - (void)recentTabsTableViewContentMoved:(UITableView*)tableView;
+
+// Tells the delegate to refresh the session view.
+- (void)refreshSessionsViewRecentTabsTableViewController:
+    (RecentTabsTableViewController*)controller;
 @end
 
 // Controls the content of a UITableView.

ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_table_view_controller.mm

@@ -525,9 +525,10 @@ enum CellType {
 #pragma mark - Distant Sessions helpers
 
 - (void)refreshUserState:(SessionsSyncUserState)newSessionState {
-  if (newSessionState == _sessionState &&
-      _sessionState !=
-          SessionsSyncUserState::USER_SIGNED_IN_SYNC_ON_WITH_SESSIONS) {
+  if ((newSessionState == _sessionState &&
+       _sessionState !=
+           SessionsSyncUserState::USER_SIGNED_IN_SYNC_ON_WITH_SESSIONS) ||
+      _signinPromoViewMediator.isSigninInProgress) {
     // No need to refresh the sections.
     return;
   }
@@ -1030,6 +1031,10 @@ enum CellType {
   [configurator configureSigninPromoView:signinPromoView];
 }
 
+- (void)signinDidFinish {
+  [self.delegate refreshSessionsViewRecentTabsTableViewController:self];
+}
+
 #pragma mark - SyncPresenter
 
 - (void)showReauthenticateSignin {