Implement important sites dialog for desktop.

chrome/browser/engagement/important_sites_util.h

 // Copyright 2016 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 CHROME_BROWSER_ENGAGEMENT_IMPORTANT_SITES_UTIL_H_
 #define CHROME_BROWSER_ENGAGEMENT_IMPORTANT_SITES_UTIL_H_
 
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "url/gurl.h"
 
 class Profile;
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 class ImportantSitesUtil {
  public:
   struct ImportantDomainInfo {
     std::string registerable_domain;
     GURL example_origin;
     double engagement_score = 0;
     int32_t reason_bitfield = 0;
   };
 
+  // Do not change the values here, as they are used for UMA histograms.

[dschuyler, 2017/04/07 00:02:05]

The comment is clear, but can it be extended to point the next coder to where
the a change/addition could be made properly? Maybe a "See: ....." line here?

[dullweber, 2017/04/07 09:39:21]

I just moved this enum from the .cc to the header to make it accessible to other
classes. I guess that new values could be appended but I have to ask Daniel
about this first.

+  enum ImportantReason {
+    ENGAGEMENT = 0,
+    DURABLE = 1,
+    BOOKMARKS = 2,
+    HOME_SCREEN = 3,
+    NOTIFICATIONS = 4,
+    REASON_BOUNDARY
+  };
+
   static bool IsDialogDisabled(Profile* profile);
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // This returns the top |<=max_results| important registrable domains. This
   // uses site engagement and notifications to generate the list. |max_results|
   // is assumed to be small.
   // See net/base/registry_controlled_domains/registry_controlled_domain.h for
   // more details on registrable domains and the current list of effective
   // eTLDs.
@@ skipping 18 matching lines @@
   // the score requirements for the Site Engagement Service, so ONLY call for
   // testing.
   static void MarkOriginAsImportantForTesting(Profile* profile,
                                               const GURL& origin);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ImportantSitesUtil);
 };
 
 #endif  // CHROME_BROWSER_ENGAGEMENT_IMPORTANT_SITES_UTIL_H_