Adding Sign-in promo for bookmark view.

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

Index: ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.h
diff --git a/ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.h b/ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.h
new file mode 100644
index 0000000000000000000000000000000000000000..415273ab8381cf36f94a6742a1bb44885e498dbf
--- /dev/null
+++ b/ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.h
@@ -0,0 +1,23 @@
+// 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_BOOKMARKS_BOOKMARK_SIGNIN_PROMO_CELL_H_
+#define IOS_CHROME_BROWSER_UI_BOOKMARKS_BOOKMARK_SIGNIN_PROMO_CELL_H_
+
+#import <UIKit/UIKit.h>
+
+@class SigninPromoView;
+
+// Sign-in promo cell based on SigninPromoView. This cell invites the user to
+// login without typing their password.
+@interface BookmarkSigninPromoCell : UICollectionViewCell
+
+// Identifier for -[UICollectionView registerClass:forCellWithReuseIdentifier:].
++ (NSString*)reuseIdentifier;
+
+@property(nonatomic, readonly) SigninPromoView* signinPromoView;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_BOOKMARKS_BOOKMARK_SIGNIN_PROMO_CELL_H_