Adding close button in SigninPromoView

ios/chrome/browser/ui/authentication/signin_promo_view.h

 // Copyright 2017 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_CHROME_BROWSER_UI_AUTHENTICATION_SIGN_PROMO_VIEW_H_
 #define IOS_CHROME_BROWSER_UI_AUTHENTICATION_SIGN_PROMO_VIEW_H_
 
 #import <UIKit/UIKit.h>
 
 @class MDCFlatButton;
@@ skipping 18 matching lines @@
 //   - the label for |textLabel|
 //   - the title for |primaryButton|
 //   - the title for |secondaryButton|
 @interface SigninPromoView : UIView
 
 @property(nonatomic) SigninPromoViewMode mode;
 @property(nonatomic, readonly) UIImageView* imageView;
 @property(nonatomic, readonly) UILabel* textLabel;
 @property(nonatomic, readonly) MDCFlatButton* primaryButton;
 @property(nonatomic, readonly) MDCFlatButton* secondaryButton;
+@property(nonatomic, readonly) UIButton* dismissButton;

[msarda, 2017/04/28 16:08:16]

Maybe add a comment saying that this button is hidden by default.

[jlebel, 2017/05/03 12:41:14]

Done.

 // If set to YES, ShowSigninCommand is sent when primary or secondary buttons
 // are tapped.
 @property(nonatomic, getter=doesSendChromeCommand) BOOL sendChromeCommand;
 
 // Horizontal padding used for |textLabel|, |primaryButton| and
 // |secondaryButton|. Used to compute the preferred max layout width of
 // |textLabel|.
 @property(nonatomic, readonly) CGFloat horizontalPadding;
 
 - (instancetype)initWithCoder:(NSCoder*)aDecoder NS_UNAVAILABLE;
 
 // Sets the image in |imageView|. This method will add a circular background
 // using CircularImageFromImage() (so if the image is not squared, it will be
 // cropped first). Must only be called in the "Warm State" mode.
 - (void)setProfileImage:(UIImage*)image;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_AUTHENTICATION_SIGN_PROMO_VIEW_H_