Convert PermissionsBlacklist flag to base::Feature.

chrome/common/chrome_features.cc

Index: chrome/common/chrome_features.cc
diff --git a/chrome/common/chrome_features.cc b/chrome/common/chrome_features.cc
index e9e847da513af8c33039dc8a6c22898c7c566fdb..4ac90dc4224dabe8cd364266c205be3dc68f5033 100644
--- a/chrome/common/chrome_features.cc
+++ b/chrome/common/chrome_features.cc
@@ -160,6 +160,10 @@ const base::Feature kOfflinePageDownloadSuggestionsFeature{
 const base::Feature kOverrideYouTubeFlashEmbed{
     "OverrideYouTubeFlashEmbed", base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Enables Permissions Blacklisting via Safe Browsing.
+const base::Feature kPermissionsBlacklist{
+    "PermissionsBlacklist", base::FEATURE_DISABLED_BY_DEFAULT};
+
 #if BUILDFLAG(ENABLE_PLUGINS)
 // Prefer HTML content by hiding Flash from the list of plugins.
 // https://crbug.com/626728