Adding Sign-in promo for bookmark view.

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
+
+@implementation BookmarkSigninPromoCell {
+  SigninPromoView* _signinPromoView;
+}
+
+@synthesize signinPromoView = _signinPromoView;
+
++ (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);
+    _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];
+}
+
+@end