Adding close button in SigninPromoView

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

Index: ios/chrome/browser/ui/authentication/signin_promo_view.mm
diff --git a/ios/chrome/browser/ui/authentication/signin_promo_view.mm b/ios/chrome/browser/ui/authentication/signin_promo_view.mm
index bab01cc0082bcd2352838d12851d0aa55fb56ac5..dce7d7fdca506b9d12962b8c2cd5fa12a41a1415 100644
--- a/ios/chrome/browser/ui/authentication/signin_promo_view.mm
+++ b/ios/chrome/browser/ui/authentication/signin_promo_view.mm
@@ -29,6 +29,8 @@ const CGFloat kButtonVerticalPadding = 6;
 const CGFloat kProfileImageFixedSize = 48;
 // Button height.
 const CGFloat kButtonHeight = 36;
+// Dismiss button size.
+const CGFloat kDismissButtonSize = 24;
 }
 
 @implementation SigninPromoView {
@@ -41,6 +43,7 @@ const CGFloat kButtonHeight = 36;
 @synthesize textLabel = _textLabel;
 @synthesize primaryButton = _primaryButton;
 @synthesize secondaryButton = _secondaryButton;
+@synthesize dismissButton = _dismissButton;
 @synthesize sendChromeCommand = _sendChromeCommand;
 
 - (instancetype)initWithFrame:(CGRect)frame {
@@ -75,6 +78,12 @@ const CGFloat kButtonHeight = 36;
                forControlEvents:UIControlEventTouchUpInside];
     [self addSubview:_secondaryButton];
 
+    _dismissButton = [[UIButton alloc]
+        initWithFrame:CGRectMake(0, 0, kDismissButtonSize, kDismissButtonSize)];
+    _dismissButton.translatesAutoresizingMaskIntoConstraints = NO;
+    _dismissButton.hidden = YES;
+    [self addSubview:_dismissButton];
+
     // Adding style.
     _imageView.contentMode = UIViewContentModeCenter;
     _imageView.layer.masksToBounds = YES;
@@ -93,6 +102,9 @@ const CGFloat kButtonHeight = 36;
     _secondaryButton.customTitleColor = [[MDCPalette cr_bluePalette] tint500];
     _secondaryButton.uppercaseTitle = NO;
 
+    [_dismissButton setImage:[UIImage imageNamed:@"signin_promo_dismiss_gray"]
+                    forState:UIControlStateNormal];
+
     // Adding constraints.
     NSDictionary* metrics = @{
       @"kButtonHeight" : @(kButtonHeight),
@@ -105,6 +117,7 @@ const CGFloat kButtonHeight = 36;
           @(kVerticalPadding + kButtonVerticalPadding),
     };
     NSDictionary* views = @{
+      @"dismissButton" : _dismissButton,
       @"imageView" : _imageView,
       @"primaryButton" : _primaryButton,
       @"secondaryButton" : _secondaryButton,
@@ -141,6 +154,11 @@ const CGFloat kButtonHeight = 36;
     _warmStateConstraints = VisualConstraintsWithMetrics(
         warmStateVisualConstraints, views, metrics);
 
+    // Constraints for the dismiss button.
+    NSArray* buttonVisualConstraints =
+        @[ @"H:[dismissButton]-|", @"V:|-[dismissButton]" ];
+    ApplyVisualConstraints(buttonVisualConstraints, views);
+
     _mode = SigninPromoViewModeColdState;
     [self activateColdMode];
   }