REALLY don't allow browser docks to arbitrarily close OBS

The previous solution only worked for code that ran *after* the page had
*finished* loading.

panel/browser-panel-client.cpp

@@ -395,6 +395,19 @@ bool QCefBrowserClient::OnContextMenuCommand(
 	return false;
 }
 
+void QCefBrowserClient::OnLoadStart(CefRefPtr<CefBrowser>,
+				    CefRefPtr<CefFrame> frame, TransitionType)
+{
+	if (!frame->IsMain())
+		return;
+
+	std::string script = "window.close = () => ";
+	script += "console.log(";
+	script += "'OBS browser docks cannot be closed using JavaScript.'";
+	script += ");";
+	frame->ExecuteJavaScript(script, "", 0);
+}
+
 void QCefBrowserClient::OnLoadEnd(CefRefPtr<CefBrowser>,
 				  CefRefPtr<CefFrame> frame, int)
 {
@@ -405,12 +418,6 @@ void QCefBrowserClient::OnLoadEnd(CefRefPtr<CefBrowser>,
 		frame->ExecuteJavaScript(widget->script, CefString(), 0);
 	else if (!script.empty())
 		frame->ExecuteJavaScript(script, CefString(), 0);
-
-	std::string script2 = "window.close = () => ";
-	script2 += "console.log(";
-	script2 += "'OBS browser docks cannot be closed using JavaScript.'";
-	script2 += ");";
-	frame->ExecuteJavaScript(script2, "", 0);
 }
 
 bool QCefBrowserClient::OnJSDialog(CefRefPtr<CefBrowser>, const CefString &,

panel/browser-panel-client.hpp

@@ -95,6 +95,10 @@ class QCefBrowserClient : public CefClient,
 		CefContextMenuHandler::EventFlags event_flags) override;
 
 	/* CefLoadHandler */
+	virtual void OnLoadStart(CefRefPtr<CefBrowser> browser,
+				 CefRefPtr<CefFrame> frame,
+				 TransitionType transition_type) override;
+
 	virtual void OnLoadEnd(CefRefPtr<CefBrowser> browser,
 			       CefRefPtr<CefFrame> frame,
 			       int httpStatusCode) override;