Add an ID to the ContentSuggestion

ios/chrome/browser/ui/content_suggestions/content_suggestion_id.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_CONTENT_SUGGESTION_ID_H_
+#define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTION_ID_H_
+
+#import <Foundation/Foundation.h>
+
+#include <string>
+
+@class ContentSuggestionsSectionInformation;
+
+// An class identifying a suggestion.
+@interface ContentSuggestionID : NSObject
+
+@property(nonatomic, strong) ContentSuggestionsSectionInformation* sectionInfo;

[gambard, 2017/02/20 09:33:14]

I am not sure about using a ContentSuggestionsSectionInformation in suggestionID
(at least the name).
Do you have an opinion?

[lpromero, 2017/02/21 10:33:34]

I am more unsure about ContentSuggestionID.IDInSection. What about:

@interface ContentSuggestionIdentifier : NSObject
@property ContentSuggestionsSection* section;
@property std::string IDInSection;
@end

@protocol ContentSuggestionIdentification
@property ContentSuggestionIdentifier* suggestionIdentifier;
@end

This is the pattern used for UIAccessibilityIdentification and
accessibilityIdentifier for example.

[gambard, 2017/02/21 14:37:48]

Done.

+// Must be unique inside a section.
+@property(nonatomic, assign) std::string IDInSection;
+
+@end
+
+// A protocol for an object having an ID.
+@protocol ContentSuggestionIDHolder
+
+@property(nonatomic, strong) ContentSuggestionID* suggestionID;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTION_ID_H_