Write last_modified date to Content Settings in the PrefProvider

components/content_settings/core/browser/host_content_settings_map.h

Index: components/content_settings/core/browser/host_content_settings_map.h
diff --git a/components/content_settings/core/browser/host_content_settings_map.h b/components/content_settings/core/browser/host_content_settings_map.h
index eadf365cfbd2aeea7914d113f75d79a4d1764d29..efa4b2a47eaf2754cdc71f10f9bc371b7386868c 100644
--- a/components/content_settings/core/browser/host_content_settings_map.h
+++ b/components/content_settings/core/browser/host_content_settings_map.h
@@ -66,7 +66,8 @@ class HostContentSettingsMap : public content_settings::Observer,
   // |is_incognito_profile| and |is_guest_profile| should be true.
   HostContentSettingsMap(PrefService* prefs,
                          bool is_incognito_profile,
-                         bool is_guest_profile);
+                         bool is_guest_profile,
+                         bool store_last_modified);
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
@@ -217,13 +218,17 @@ class HostContentSettingsMap : public content_settings::Observer,
   // This should only be called on the UI thread.
   void ClearSettingsForOneType(ContentSettingsType content_type);
 
+  using PatternSourcePredicate =
+      base::Callback<bool(const ContentSettingsPattern& primary_pattern,
+                          const ContentSettingsPattern& secondary_pattern,
+                          base::Time last_modified)>;
+
   // If |pattern_predicate| is null, this method is equivalent to the above.
   // Otherwise, it only deletes exceptions matched by |pattern_predicate|.
   void ClearSettingsForOneTypeWithPredicate(
       ContentSettingsType content_type,
-      const base::Callback<bool(
-          const ContentSettingsPattern& primary_pattern,
-          const ContentSettingsPattern& secondary_pattern)>& pattern_predicate);
+      const std::string& resource_identifier,
+      const PatternSourcePredicate& pattern_predicate);
 
   static bool IsDefaultSettingAllowedForType(ContentSetting setting,
                                              ContentSettingsType content_type);
@@ -358,6 +363,10 @@ class HostContentSettingsMap : public content_settings::Observer,
   // Whether this settings map is for an incognito session.
   bool is_incognito_;
 
+  // Whether ContentSettings in the PrefProvider will store a last_modified
+  // timestamp.
+  bool store_last_modified_;
+
   // Content setting providers. This is only modified at construction
   // time and by RegisterExtensionService, both of which should happen
   // before any other uses of it.