UI: Shut down browsers when browser docks hidden

Shuts down the actual browsers internally when the browser docks are
hidden by user.

UI/CMakeLists.txt

@@ -146,6 +146,7 @@ if(BROWSER_AVAILABLE_INTERNAL)
 	list(APPEND obs_PLATFORM_SOURCES
 		obf.c
 		auth-oauth.cpp
+		window-dock-browser.cpp
 		window-extra-browsers.cpp
 		)
 	list(APPEND obs_PLATFORM_HEADERS

UI/window-dock-browser.cpp

@@ -0,0 +1,20 @@
+#include "window-dock-browser.hpp"
+#include <QCloseEvent>
+
+void BrowserDock::closeEvent(QCloseEvent *event)
+{
+	OBSDock::closeEvent(event);
+
+	if (!event->isAccepted()) {
+		return;
+	}
+
+	static int panel_version = -1;
+	if (panel_version == -1) {
+		panel_version = obs_browser_qcef_version();
+	}
+
+	if (panel_version >= 2) {
+		cefWidget->closeBrowser();
+	}
+}

UI/window-dock-browser.hpp

@@ -18,4 +18,6 @@ public:
 		setWidget(widget_);
 		cefWidget.reset(widget_);
 	}
+
+	void closeEvent(QCloseEvent *event) override;
 };