Unity WebWindow (browser within unity editor window, helpful for tools that require a web view or more beyond basic controls).

WebWindow.cs

using UnityEngine;
using UnityEditor;
using System;
using System.Reflection;

public class WebWindow : EditorWindow {
  
	static Rect windowRect = new Rect(100,100,800,600);
	static BindingFlags fullBinding = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
	static StringComparison ignoreCase = StringComparison.CurrentCultureIgnoreCase;
	
	object webView;
	dynamic x;
	Type webViewType;
	MethodInfo doGUIMethod;
	MethodInfo loadURLMethod;
	MethodInfo focusMethod;
	MethodInfo unFocusMethod;
	
	Vector2 resizeStartPos;
	Rect resizeStartWindowSize;
	MethodInfo dockedGetterMethod;
	
	string urlText = "http://www.google.com";
	

	[MenuItem ("Tools/Web Window %#w")]
    static void Load() {
        WebWindow window = WebWindow.GetWindow<WebWindow>();
		//window.Show();
		window.Init();
    }
	
	void Init() {
		//Set window rect
		this.position = windowRect;
		//Get WebView type
		webViewType = GetTypeFromAllAssemblies("WebView");
		//Init web view
		InitWebView();
		//Get docked property getter MethodInfo
		dockedGetterMethod = typeof(EditorWindow).GetProperty("docked", fullBinding).GetGetMethod(true);
	}
	
	private void InitWebView() {
		webView = ScriptableObject.CreateInstance(webViewType);
		webViewType.GetMethod("InitWebView").Invoke(webView, new object[] {(int)position.width,(int)position.height,false});
		webViewType.GetMethod("set_hideFlags").Invoke(webView, new object[] {13});
		
		loadURLMethod = webViewType.GetMethod("LoadURL");
		loadURLMethod.Invoke(webView, new object[] {urlText});
		webViewType.GetMethod("SetDelegateObject").Invoke(webView, new object[] {this});
		
		doGUIMethod = webViewType.GetMethod("DoGUI");
		focusMethod = webViewType.GetMethod("Focus");
		unFocusMethod = webViewType.GetMethod("UnFocus");
		
		this.wantsMouseMove = true;
	}
	
	void OnGUI() {
		if(GUI.GetNameOfFocusedControl().Equals("urlfield"))
			unFocusMethod.Invoke(webView, null);
		
		bool isDocked = (bool)(dockedGetterMethod.Invoke(this, null));
		Rect webViewRect = new Rect(0,20,position.width,position.height - ((isDocked) ? 20 : 40));
		if(Event.current.isMouse && Event.current.type == EventType.MouseDown && webViewRect.Contains(Event.current.mousePosition)) {
			GUI.FocusControl("hidden");
			focusMethod.Invoke(webView, null);
		}
		
		//Hidden, disabled, button for taking focus away from urlfield
		GUI.enabled = false;
		GUI.SetNextControlName("hidden");
		GUI.Button(new Rect(-20,-20,5,5), string.Empty);
		GUI.enabled = true;
		
		//URL Label
		GUI.Label(new Rect(0,0,30,20), "URL:");
		
		//URL text field
		GUI.SetNextControlName("urlfield"); 
		urlText = GUI.TextField(new Rect(30,0, position.width-30, 20), urlText);
		
		//Focus on web view if return is pressed in URL field
		if(Event.current.isKey && Event.current.keyCode == KeyCode.Return && GUI.GetNameOfFocusedControl().Equals("urlfield")) {
			loadURLMethod.Invoke(webView, new object[] {urlText});
			GUI.FocusControl("hidden");
			focusMethod.Invoke(webView, null);
		}
		
		//Web view
		if(webView != null)
			doGUIMethod.Invoke(webView, new object[] {webViewRect});
	}
	
	private void OnWebViewDirty() {
		this.Repaint();
	}
	
	public static Type GetTypeFromAllAssemblies(string typeName) {
		Assembly[] assemblies = System.AppDomain.CurrentDomain.GetAssemblies();
		foreach(Assembly assembly in assemblies) {
			Type[] types = assembly.GetTypes();
			foreach(Type type in types) {
				if(type.Name.Equals(typeName, ignoreCase) || type.Name.Contains('+' + typeName)) //+ check for inline classes
					return type;
			}
		}
		return null;
	}
	
	void OnDestroy() {
		//Destroy web view
		webViewType.GetMethod("DestroyWebView", fullBinding).Invoke(webView, null);
	}
}

Thank you very much for this script. Great job.
I have one question, now "InitWebView" method request 5 parameters and first among them is "GUIView" which also can be obtained only from reflection. How to pass it in "Invoke"?

Thank you in advance.

Thank you sooooooooooooooooooo much for this! I've been searching this for a long time. I'm making an embedded design document tool for designers. This helps a lot! Some code no longer works but still, it is a good example to start.

This seems to no longer work. It can't find the type inside any assembly They must have made it more private in 2020