[ObjC ARC] Converts ios/public/provider/chrome/browser/signin:signin to ARC.

ios/public/provider/chrome/browser/signin/chrome_identity_interaction_manager.h

 // 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.
 
 #ifndef IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_CHROME_IDENTITY_INTERACTION_MANAGER_H_
 #define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_CHROME_IDENTITY_INTERACTION_MANAGER_H_
 
 #import <UIKit/UIKit.h>
 
 #import "base/ios/block_types.h"
@@ skipping 12 matching lines @@
 // * |identity| is the identity that was added/reauthenticated.
 // * |error| is nil unless there was an error during the operation.
 typedef void (^SigninCompletionCallback)(ChromeIdentity* identity,
                                          NSError* error);
 
 // ChromeIdentityInteractionManager abstracts the interaction to add identities
 // on iOS.
 @interface ChromeIdentityInteractionManager : NSObject
 
 // Delegate used to present and dismiss the view controllers.
-@property(nonatomic, assign) id<ChromeIdentityInteractionManagerDelegate>
+@property(nonatomic, weak) id<ChromeIdentityInteractionManagerDelegate>
     delegate;
 
 // Whether the manager is currently being canceled. Delegates may inquire if the
 // dismissal is due to sign-in being canceled.
 @property(nonatomic, readonly) BOOL isCanceling;
 
 // Starts the add account operation for a user. Presents user with the screen to
 // enter credentials.
 // Note: Calling this method will fail and the completion will be called with a
 // CHROME_IDENTITY_OPERATION_ONGOING error if there is already another add
@@ skipping 43 matching lines @@
 //   animation.
 // * |completion| is the completion block to call once the dismissal operation
 //   is finished.
 - (void)interactionManager:(ChromeIdentityInteractionManager*)interactionManager
     dismissViewControllerAnimated:(BOOL)animated
                        completion:(ProceduralBlock)completion;
 
 @end
 
 #endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_CHROME_IDENTITY_INTERACTION_MANAGER_H_