Revert of Removes usage of signin APIs that return scoped_nsobjects.

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

 // Copyright 2015 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/chrome_signin_view_controller.h"
 
 #include <stdint.h>
 #include <cmath>
 #include <memory>
 
@@ skipping 340 matching lines @@
   [_authenticationFlow startSignInWithCompletion:^(BOOL success) {
     [weakSelf onAccountSigninCompletion:success];
   }];
 }
 
 - (void)openAuthenticationDialogAddIdentity {
   DCHECK(!_interactionManager);
   _interactionManager =
       ios::GetChromeBrowserProvider()
           ->GetChromeIdentityService()
-          ->CreateChromeIdentityInteractionManager(_browserState, self);
+          ->NewChromeIdentityInteractionManager(_browserState, self);
   __weak ChromeSigninViewController* weakSelf = self;
   SigninCompletionCallback completion =
       ^(ChromeIdentity* identity, NSError* error) {
         ChromeSigninViewController* strongSelf = weakSelf;
         if (!strongSelf || !strongSelf->_interactionManager)
           return;
         // The ChromeIdentityInteractionManager is not used anymore at this
         // point.
         strongSelf->_interactionManager = nil;
 
@@ skipping 563 matching lines @@
   }
   _hasConfirmationScreenReachedBottom = YES;
   [self setPrimaryButtonStyling:_primaryButton];
   [_primaryButton setTitle:[self acceptSigninButtonTitle]
                   forState:UIControlStateNormal];
   [_primaryButton setImage:nil forState:UIControlStateNormal];
   [self.view setNeedsLayout];
 }
 
 @end