UI: Add the ability to create custom browser docks

Allows the ability for users to add custom browser widget docks that
they can use for their third party services if they feel the need,
mostly as a convenience tool so they don't have to open extra browsers
alongside the program.

UI/window-basic-main.cpp

@@ -1689,6 +1689,23 @@ void OBSBasic::OBSInit()
 	OBSBasicStats *statsDlg = new OBSBasicStats(statsDock, false);
 	statsDock->setWidget(statsDlg);
 
+	/* ----------------------------- */
+	/* add custom browser docks      */
+
+#ifdef BROWSER_AVAILABLE
+	if (cef) {
+		QAction *action = new QAction(QTStr("Basic.MainMenu."
+						    "View.Docks."
+						    "CustomBrowserDocks"));
+		ui->viewMenuDocks->insertAction(ui->toggleScenes, action);
+		connect(action, &QAction::triggered, this,
+			&OBSBasic::ManageExtraBrowserDocks);
+		ui->viewMenuDocks->insertSeparator(ui->toggleScenes);
+
+		LoadExtraBrowserDocks();
+	}
+#endif
+
 	const char *dockStateStr = config_get_string(
 		App()->GlobalConfig(), "BasicWindow", "DockState");
 	if (!dockStateStr) {
@@ -3794,9 +3811,16 @@ void OBSBasic::closeEvent(QCloseEvent *event)
 	SaveProjectNow();
 	auth.reset();
 
+	delete extraBrowsers;
+
 	config_set_string(App()->GlobalConfig(), "BasicWindow", "DockState",
 			  saveState().toBase64().constData());
 
+#ifdef BROWSER_AVAILABLE
+	SaveExtraBrowserDocks();
+	ClearExtraBrowserDocks();
+#endif
+
 	if (api)
 		api->on_event(OBS_FRONTEND_EVENT_EXIT);