Ntp: use AMP urls for content suggestions when available.

components/ntp_snippets/content_suggestion.h

Index: components/ntp_snippets/content_suggestion.h
diff --git a/components/ntp_snippets/content_suggestion.h b/components/ntp_snippets/content_suggestion.h
index 992dd02d035e0fa0b6a89184df00d5416fb57ccd..50044172ff4ed0fc29c45c8c90fad009ad6638c0 100644
--- a/components/ntp_snippets/content_suggestion.h
+++ b/components/ntp_snippets/content_suggestion.h
@@ -86,11 +86,6 @@ class ContentSuggestion {
   // be accessed.
   const GURL& url() const { return url_; }
 
-  // If available, this contains an URL to an AMP version of the same content.
-  // Otherwise, this is an empty GURL().
-  const GURL& amp_url() const { return amp_url_; }
-  void set_amp_url(const GURL& amp_url) { amp_url_ = amp_url; }
-
   // Title of the suggestion.
   const base::string16& title() const { return title_; }
   void set_title(const base::string16& title) { title_ = title; }
@@ -141,7 +136,6 @@ class ContentSuggestion {
  private:
   ID id_;
   GURL url_;
-  GURL amp_url_;
   base::string16 title_;
   base::string16 snippet_text_;
   base::Time publish_date_;