[Signin iOS] Ensure SigninInteractionController displays signin errors.

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

 // Copyright 2014 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.
 
 #import "ios/chrome/browser/ui/authentication/signin_interaction_controller.h"
 
 #include "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/scoped_block.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/prefs/pref_service.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/signin/core/common/signin_pref_names.h"
 #import "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/signin/authentication_service.h"
 #include "ios/chrome/browser/signin/authentication_service_factory.h"
 #include "ios/chrome/browser/signin/signin_manager_factory.h"
 #import "ios/chrome/browser/signin/signin_util.h"
 #import "ios/chrome/browser/ui/alert_coordinator/alert_coordinator.h"
 #import "ios/chrome/browser/ui/authentication/authentication_ui_util.h"
 #import "ios/chrome/browser/ui/authentication/chrome_signin_view_controller.h"
 #import "ios/chrome/browser/ui/commands/UIKit+ChromeExecuteCommand.h"
+#import "ios/chrome/browser/ui/util/top_view_controller.h"
 #import "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #import "ios/public/provider/chrome/browser/signin/chrome_identity.h"
 #import "ios/public/provider/chrome/browser/signin/chrome_identity_interaction_manager.h"
 #import "ios/public/provider/chrome/browser/signin/chrome_identity_service.h"
 
 using signin_ui::CompletionCallback;
 
 @interface SigninInteractionController ()<
     ChromeIdentityInteractionManagerDelegate,
     ChromeSigninViewControllerDelegate> {
@@ skipping 159 matching lines @@
       [self runCompletionCallbackWithSuccess:NO executeCommand:nil];
       return;
     }
 
     base::WeakNSObject<SigninInteractionController> weakSelf(self);
     ProceduralBlock dismissAction = ^{
       [weakSelf runCompletionCallbackWithSuccess:NO executeCommand:nil];
     };
 
     alertCoordinator_.reset([ios_internal::ErrorCoordinator(
-        error, dismissAction, viewController) retain]);
+        error, dismissAction,
+        top_view_controller::TopPresentedViewControllerFrom(viewController))
+        retain]);
     [alertCoordinator_ start];
     return;
   }
   if (shouldSignIn) {
     [self showSigninViewControllerWithIdentity:identity];
   } else {
     [self runCompletionCallbackWithSuccess:YES executeCommand:nil];
   }
 }
 
@@ skipping 151 matching lines @@
     completionCallback_.get()(success);
     completionCallback_.reset();
   }
   strongSelf.reset();
   if (command) {
     [presentingViewController chromeExecuteCommand:command];
   }
 }
 
 @end