[NTP::PhysicalWeb] Implement suggestion dismissal.

components/ntp_snippets/pref_names.cc

Index: components/ntp_snippets/pref_names.cc
diff --git a/components/ntp_snippets/pref_names.cc b/components/ntp_snippets/pref_names.cc
index 9b0ff032e9d7b99bcffa595d257248d1175b0897..b05931e070a3296179bfe0cc57ed4a0ac5149437 100644
--- a/components/ntp_snippets/pref_names.cc
+++ b/components/ntp_snippets/pref_names.cc
@@ -33,12 +33,15 @@ const char kSnippetThumbnailsRequestsDay[] =
 
 const char kDismissedAssetDownloadSuggestions[] =
     "ntp_suggestions.downloads.assets.dismissed_ids";
-const char kDismissedRecentOfflineTabSuggestions[] =
-    "ntp_suggestions.offline_pages.recent_tabs.dismissed_ids";
-const char kDismissedOfflinePageDownloadSuggestions[] =
-    "ntp_suggestions.downloads.offline_pages.dismissed_ids";
 const char kDismissedForeignSessionsSuggestions[] =
     "ntp_suggestions.foreign_sessions.dismissed_ids";
+const char kDismissedOfflinePageDownloadSuggestions[] =
+    "ntp_suggestions.downloads.offline_pages.dismissed_ids";
+const char kDismissedPhysicalWebPageSuggestions[] =
+    "ntp_suggestions.physical_web.dismissed_ids";
+const char kDismissedRecentOfflineTabSuggestions[] =
+    "ntp_suggestions.offline_pages.recent_tabs.dismissed_ids";
+
 const char kDismissedCategories[] = "ntp_suggestions.dismissed_categories";
 
 const char kUserClassifierAverageNTPOpenedPerHour[] =