vulkan: Handle changing window scale

The code that checks for the proper size of the our swapchain
was not taking window scale fully into account. With this change,
setting the window scale to 2 in the inspector causes the window
to grow and rendering to be scaled up as expected, with Vulkan,
in the same way it already is with cairo.

gdk/gdkvulkancontext.c

@@ -195,8 +195,8 @@ gdk_vulkan_context_check_swapchain (GdkVulkanContext  *context,
   VkDevice device;
   guint i;
 
-  if (gdk_window_get_width (window) == priv->swapchain_width &&
-      gdk_window_get_height (window) == priv->swapchain_height)
+  if (gdk_window_get_width (window) * gdk_window_get_scale_factor (window) == priv->swapchain_width &&
+      gdk_window_get_height (window) * gdk_window_get_scale_factor (window) == priv->swapchain_height)
     return TRUE;
 
   device = gdk_vulkan_context_get_device (context);