Adding close button in SigninPromoView

ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.mm

 // 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.
 
 #import "ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.h"
 
 #import "ios/chrome/browser/ui/authentication/signin_promo_view.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #include "ios/chrome/grit/ios_chromium_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
+namespace {
+// Close button size.
+const CGFloat kCloseButtonSize = 24;
+}
+
 @implementation BookmarkSigninPromoCell {
   SigninPromoView* _signinPromoView;
+  UIButton* _closeButton;
 }
 
 @synthesize signinPromoView = _signinPromoView;
+@synthesize closeButtonAction = _closeButtonAction;
 
 + (NSString*)reuseIdentifier {
   return @"BookmarkSigninPromoCell";
 }
 
 + (BOOL)requiresConstraintBasedLayout {
   return YES;
 }
 
 - (instancetype)initWithFrame:(CGRect)frame {
   self = [super initWithFrame:frame];
   if (self) {
     UIView* contentView = self.contentView;
     _signinPromoView = [[SigninPromoView alloc] initWithFrame:self.bounds];
     _signinPromoView.translatesAutoresizingMaskIntoConstraints = NO;
     [contentView addSubview:_signinPromoView];
     AddSameConstraints(_signinPromoView, contentView);
+
+    _closeButton = [[UIButton alloc]
+        initWithFrame:CGRectMake(0, 0, kCloseButtonSize, kCloseButtonSize)];
+    [_closeButton addTarget:self
+                     action:@selector(closeButtonAction:)
+           forControlEvents:UIControlEventTouchUpInside];
+    _closeButton.translatesAutoresizingMaskIntoConstraints = NO;
+    [contentView addSubview:_closeButton];
+    [_closeButton setImage:[UIImage imageNamed:@"signin_promo_close_gray"]
+                  forState:UIControlStateNormal];
+    NSArray* buttonVisualConstraints =
+        @[ @"H:[closeButton]-|", @"V:|-[closeButton]" ];
+    NSDictionary* views = @{ @"closeButton" : _closeButton };
+    ApplyVisualConstraints(buttonVisualConstraints, views);
+
     _signinPromoView.backgroundColor = [UIColor whiteColor];
     _signinPromoView.textLabel.text =
         l10n_util::GetNSString(IDS_IOS_SIGNIN_PROMO_SETTINGS);
   }
   return self;
 }
 
 - (void)layoutSubviews {
   // Adjust the text label preferredMaxLayoutWidth according self.frame.width,
   // so the text will adjust its height and not its width.
   CGFloat parentWidth = CGRectGetWidth(self.bounds);
   _signinPromoView.textLabel.preferredMaxLayoutWidth =
       parentWidth - 2 * _signinPromoView.horizontalPadding;
 
   // Re-layout with the new preferred width to allow the label to adjust its
   // height.
   [super layoutSubviews];
 }
 
+- (void)prepareForReuse {
+  _closeButtonAction = nil;
+}
+
+- (void)closeButtonAction:(id)sender {
+  if (_closeButtonAction) {
+    _closeButtonAction();

[msarda, 2017/05/04 11:48:08]

I think it would be better to set the closeButtonAction to nil after it is
called once. This would avoid it being called multiple times if the user taps
quickly more than once on the close button.

[jlebel, 2017/05/04 13:20:38]

I don't believe it is relevant. This should be done where the action is done.

+  }
+}
+
 @end