Add a message to empty ContentSuggestions sections

ios/chrome/browser/ui/content_suggestions/identifier/content_suggestions_section_information.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_CONTENT_SUGGESTIONS_IDENTIFIER_CONTENT_SUGGESTIONS_SECTION_INFORMATION_H_
 #define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_IDENTIFIER_CONTENT_SUGGESTIONS_SECTION_INFORMATION_H_
 
 #import <Foundation/Foundation.h>
 
 // Layout for the section and its items.
@@ skipping 25 matching lines @@
 - (instancetype)init NS_UNAVAILABLE;
 
 // Layout to display the content of the section.
 @property(nonatomic, assign) ContentSuggestionsSectionLayout layout;
 // ID of the section. Used for ordering.
 @property(nonatomic, assign, readonly) ContentSuggestionsSectionID sectionID;
 // Title for the section.
 @property(nonatomic, copy) NSString* title;
 // Title of the section's footer. If it is nil, no footer is created.
 @property(nonatomic, copy) NSString* footerTitle;
+// Text to be displayed when the section is empty.
+@property(nonatomic, copy) NSString* emptyText;
+// If the section should be shown when empty at loading. If the section becomes
+// empty because the user dismissed suggestions, the |emptyText| must be shown
+// in both cases.
+@property(nonatomic, assign) BOOL showIfEmpty;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_IDENTIFIER_CONTENT_SUGGESTIONS_SECTION_INFORMATION_H_