Add Ephemeral provider to site settings counter.

Ephemeral provider is added to the list of content settings sources that
are counted in site settings change counter.

Bug: 762560
Change-Id: I526f7280b61b4f777560c58a99cf5148bd9b9ff9
Reviewed-on: https://chromium-review.googlesource.com/1155603Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579355}

chrome/browser/browsing_data/counters/site_settings_counter.cc

@@ -53,7 +53,8 @@ void SiteSettingsCounter::Count() {
       // TODO(crbug.com/762560): Check the conceptual SettingSource instead of
       // ContentSettingPatternSource.source
       if (content_setting.source == "preference" ||
-          content_setting.source == "notification_android") {
+          content_setting.source == "notification_android" ||
+          content_setting.source == "ephemeral") {
         base::Time last_modified = map_->GetSettingLastModifiedDate(
             content_setting.primary_pattern, content_setting.secondary_pattern,
             type);