views: Add support for absolute positioned overlay views.

To test:
Run `cefclient.exe --use-views --hide-frame --hide-controls`
Add `--enable-chrome-runtime` for the same behavior using the Chrome location
bar instead of a text field.

libcef_dll/cpptoc/views/overlay_controller_cpptoc.h

@@ -0,0 +1,42 @@
+// Copyright (c) 2021 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.
+//
+// ---------------------------------------------------------------------------
+//
+// This file was generated by the CEF translator tool. If making changes by
+// hand only do so within the body of existing method and function
+// implementations. See the translator.README.txt file in the tools directory
+// for more information.
+//
+// $hash=a35c34c93f38c7db53ddd261a1631ef52d0f5ab5$
+//
+
+#ifndef CEF_LIBCEF_DLL_CPPTOC_VIEWS_OVERLAY_CONTROLLER_CPPTOC_H_
+#define CEF_LIBCEF_DLL_CPPTOC_VIEWS_OVERLAY_CONTROLLER_CPPTOC_H_
+#pragma once
+
+#if !defined(BUILDING_CEF_SHARED)
+#error This file can be included DLL-side only
+#endif
+
+#include "include/capi/views/cef_overlay_controller_capi.h"
+#include "include/capi/views/cef_view_capi.h"
+#include "include/capi/views/cef_window_capi.h"
+#include "include/views/cef_overlay_controller.h"
+#include "include/views/cef_view.h"
+#include "include/views/cef_window.h"
+#include "libcef_dll/cpptoc/cpptoc_ref_counted.h"
+
+// Wrap a C++ class with a C structure.
+// This class may be instantiated and accessed DLL-side only.
+class CefOverlayControllerCppToC
+    : public CefCppToCRefCounted<CefOverlayControllerCppToC,
+                                 CefOverlayController,
+                                 cef_overlay_controller_t> {
+ public:
+  CefOverlayControllerCppToC();
+  virtual ~CefOverlayControllerCppToC();
+};
+
+#endif  // CEF_LIBCEF_DLL_CPPTOC_VIEWS_OVERLAY_CONTROLLER_CPPTOC_H_