Add a feature to display a persistence toggle for permission prompts on Android.

chrome/browser/permissions/permission_util.h

Index: chrome/browser/permissions/permission_util.h
diff --git a/chrome/browser/permissions/permission_util.h b/chrome/browser/permissions/permission_util.h
index b0bf557b01e8930ca43e87c44250f4e530bf2f46..414278b848019d8a2665f510e244547ce17de978 100644
--- a/chrome/browser/permissions/permission_util.h
+++ b/chrome/browser/permissions/permission_util.h
@@ -20,6 +20,20 @@ enum class PermissionType;
 
 enum class PermissionSourceUI;
 
+// This enum backs a UMA histogram, so it must be treated as append-only.
+enum PermissionAction {
+  GRANTED = 0,
+  DENIED = 1,
+  DISMISSED = 2,
+  IGNORED = 3,
+  REVOKED = 4,
+  REENABLED = 5,
+  REQUESTED = 6,
+
+  // Always keep this at the end.
+  PERMISSION_ACTION_NUM,
+};
+
 struct PermissionTypeHash {
   std::size_t operator()(const content::PermissionType& type) const;
 };