Add callback to allow Document PiP moveTo/By() (fixes #3714)

Allow Document picture-in-picture moveTo/By() and resizeTo/By()
(without user gesture) if the new
CefBrowserViewDelegate::AllowMoveForPictureInPicture callback
returns true.

libcef/renderer/browser_config.h

@@ -0,0 +1,22 @@
+// Copyright 2025 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_RENDERER_BROWSER_CONFIG_H_
+#define CEF_LIBCEF_RENDERER_BROWSER_CONFIG_H_
+#pragma once
+
+namespace cef {
+
+// CefBrowser configuration determined prior to CefBrowserHost creation (in
+// CefBrowserPlatformDelegate::GetBrowserConfig) and passed to the renderer
+// process via the GetNewBrowserInfo Mojo request.
+struct BrowserConfig {
+  bool is_windowless;
+  bool print_preview_enabled;
+  bool move_pip_enabled;
+};
+
+}  // namespace cef
+
+#endif  // CEF_LIBCEF_RENDERER_BROWSER_CONFIG_H_