UI: Close display before native surfaces

This hooks the platform specific events in order to close the obs
display more accurately. Earlier attempts on hooking visiblity, but Qt
does not ensure that visibility is changed before the surface is
destroyed. So we ended up racing with the EGL driver and on some
drivers if you lose the race they hang.

Also only force display creation if the display is actually visible.
When a source type is not video/drawable (or is missing) this would
force the display to be created for the blank window and also hang.

Finally force closure of the preview displays during scene cleanup to
avoid similar ordering issues in Qt. Qt has even less order guarentees
during close and we are sure that displays are no longer needed at this
point in the UI.

UI/qt-display.cpp

@@ -42,6 +42,9 @@ protected:
 			else
 				mTimerId = startTimer(67); // Arbitrary
 			break;
+		case QPlatformSurfaceEvent::SurfaceAboutToBeDestroyed:
+			display->DestroyDisplay();
+			break;
 		case QEvent::Expose:
 			createOBSDisplay();
 			break;
@@ -52,7 +55,10 @@ protected:
 		return result;
 	}
 
-	void timerEvent(QTimerEvent *) { createOBSDisplay(true); }
+	void timerEvent(QTimerEvent *)
+	{
+		createOBSDisplay(display->isVisible());
+	}
 
 private:
 	void createOBSDisplay(bool force = false)

UI/qt-display.hpp

@@ -43,6 +43,7 @@ public:
 	void SetDisplayBackgroundColor(const QColor &color);
 	void UpdateDisplayBackgroundColor();
 	void CreateDisplay(bool force = false);
+	void DestroyDisplay() { display = nullptr; };
 
 	void OnMove();
 	void OnDisplayChange();

UI/window-basic-main.cpp

@@ -4707,6 +4707,10 @@ void OBSBasic::closeEvent(QCloseEvent *event)
 
 	delete extraBrowsers;
 
+	ui->preview->DestroyDisplay();
+	if (program)
+		program->DestroyDisplay();
+
 	config_set_string(App()->GlobalConfig(), "BasicWindow", "DockState",
 			  saveState().toBase64().constData());