Method to watch a child windows messages specifically for use with CefSharp Chromium Embedded Web Browser

gistfile1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Security;
using System.Text;
using System.Windows.Forms;
using CefSharp;
using CefSharp.WinForms;

namespace WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        private const int GWL_WNDPROC = -4;

        [DllImport("User32.Dll")]
        public static extern int GetClassName(IntPtr hwnd, StringBuilder lpClassName, int nMaxCount);

        [DllImport("user32.dll")]
        private static extern bool EnumChildWindows(IntPtr hwndParent, EnumWindowsProc lpEnumFunc, IntPtr lParam);

        [DllImport("user32.dll", EntryPoint = "GetWindowLong")]
        private static extern IntPtr GetWindowLong(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll", EntryPoint = "SetWindowLong")]
        private static extern IntPtr SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong);

        [SuppressUnmanagedCodeSecurity, SecurityCritical, DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr CallWindowProc(IntPtr wndProc, IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        [UnmanagedFunctionPointer(CallingConvention.Winapi)]
        private delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);

        [UnmanagedFunctionPointer(CallingConvention.Winapi)]
        private delegate IntPtr WndProcDelegate(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        public static List<IntPtr> GetChildWindows(IntPtr parent)
        {
            var result = new List<IntPtr>();
            var listHandle = GCHandle.Alloc(result);
            try
            {
                var childProc = new EnumWindowsProc(EnumWindow);
                EnumChildWindows(parent, childProc, GCHandle.ToIntPtr(listHandle));
            }
            finally
            {
                if (listHandle.IsAllocated)
                {
                    listHandle.Free();
                }
            }
            return result;
        }

        private static bool EnumWindow(IntPtr handle, IntPtr pointer)
        {
            var gch = GCHandle.FromIntPtr(pointer);
            var list = gch.Target as List<IntPtr>;
            if (list == null)
            {
                throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
            }
            list.Add(handle);
            return true;
        }

        private readonly WebView _webView;
        private IntPtr _oldWebViewWndProc;

        public Form2()
        {
            InitializeComponent();

            if (CEF.Initialize(new Settings { PackLoadingDisabled = true }))
            {
                _webView = new WebView("http://www.google.com", new BrowserSettings()) {Dock = DockStyle.Fill};
                _webView.PropertyChanged += WebViewPropertyChanged;
                Controls.Add(_webView);
            }
        }

        private void WebViewPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == "IsBrowserInitialized" && _webView.IsBrowserInitialized)
            {
                //this is on the WebView UI thread need to invoke back into the Form UI thread
                BeginInvoke(new Action(() =>
                {
                    //get through child windows looking for the WebViewHost
                    foreach (var childWindow in GetChildWindows(Handle))
                    {
                        var className = new StringBuilder(100);
                        GetClassName(childWindow, className, className.Capacity);
                        if (className.ToString() == "WebViewHost")
                        {
                            //add a watcher to the WebView wndproc messages
                            WatchWebViewWndProc(childWindow);
                        }
                    }
                }));
            }
        }

        private void WatchWebViewWndProc(IntPtr hwnd)
        {
            //get current WndProc to pass message onto
            _oldWebViewWndProc = GetWindowLong(hwnd, GWL_WNDPROC);

            //overwrite WebView wndprox with our own
            SetWindowLong(hwnd, GWL_WNDPROC, Marshal.GetFunctionPointerForDelegate(new WndProcDelegate(WebViewWndProc)));
        }

        private IntPtr WebViewWndProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam)
        {
            if (msg == 0x0084) //WM_NCHITEST
            {
                Debug.Print("WEBVIEW WM_NCHITEST");
            }
            //always pass onto original WndProc
            return CallWindowProc(_oldWebViewWndProc, hWnd, msg, wParam, lParam);
        }

        protected override void WndProc(ref Message m)
        {
            if (m.Msg == 0x0083) //WM_NCAlSIZE
            {
            }
            if (m.Msg == 0x0084) //WM_NCHITEST
            {
                Debug.Print("FORM WM_NCHITEST");
            }
            base.WndProc(ref m);
        }
    }
}

Hello. This looks good, however I am using Xilium.Cefglue, which as far as I can tell does not have the WebViewPropertyChanged event. Is there a way to work around that?