Add a message to empty ContentSuggestions sections

ios/chrome/browser/ui/content_suggestions/identifier/content_suggestions_section_information.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/content_suggestions/identifier/content_suggestions_section_information.h"
 
 #include "base/logging.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 @implementation ContentSuggestionsSectionInformation
 
 @synthesize layout = _layout;
 @synthesize sectionID = _sectionID;
 @synthesize title = _title;
 @synthesize footerTitle = _footerTitle;
+@synthesize emptyText = _emptyText;
+@synthesize showIfEmpty = _showIfEmpty;
 
 - (instancetype)initWithSectionID:(ContentSuggestionsSectionID)sectionID {
   self = [super init];
   if (self) {
     DCHECK(sectionID < ContentSuggestionsSectionUnknown);
     _sectionID = sectionID;
   }
   return self;
 }
 
 @end