Add CefPermissionHandler callbacks for permission prompts (see issue #3352)

libcef/browser/permission_prompt.h

@@ -0,0 +1,15 @@
+// Copyright 2022 The Chromium Embedded Framework Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be found
+// in the LICENSE file.
+
+#ifndef CEF_LIBCEF_BROWSER_PERMISSION_PROMPT_H_
+#define CEF_LIBCEF_BROWSER_PERMISSION_PROMPT_H_
+#pragma once
+
+namespace permission_prompt {
+
+void RegisterCreateCallback();
+
+}  // namespace permission_prompt
+
+#endif  // CEF_LIBCEF_BROWSER_PERMISSION_PROMPT_H_