wayland: fix wl_surface_set_buffer_scale usage

The wl_surface lives for the entire lifetime of the vo. It's only
neccesary to set the scale initially and when the output scaling changes
(the surface moves to a different output with a different scale or the
output itself changes it scale). All of the calls that were being made
in the egl/vulkan resize functions are not needed. vo_wlshm wasn't
correctly rescaling itself before this commit since it had no logic to
handle scale changes. This should all be shared, common code in the
surface/output listeners.

video/out/opengl/context_wayland.c

@@ -47,8 +47,6 @@ static void resize(struct ra_ctx *ctx)
     const int32_t height = wl->scaling * mp_rect_h(wl->geometry);
 
     vo_wayland_set_opaque_region(wl, ctx->opts.want_alpha);
-    wl_surface_set_buffer_scale(wl->surface, wl->scaling);
-
     if (p->egl_window)
         wl_egl_window_resize(p->egl_window, width, height, 0, 0);
 

video/out/vulkan/context_wayland.c

@@ -124,7 +124,6 @@ static bool resize(struct ra_ctx *ctx)
     const int32_t height = wl->scaling * mp_rect_h(wl->geometry);
 
     vo_wayland_set_opaque_region(wl, ctx->opts.want_alpha);
-    wl_surface_set_buffer_scale(wl->surface, wl->scaling);
     return ra_vk_ctx_resize(ctx, width, height);
 }
 

video/out/wayland_common.c

@@ -653,6 +653,7 @@ static void output_handle_done(void* data, struct wl_output *wl_output)
      * geometry and scaling should be recalculated. */
     if (wl->current_output && wl->current_output->output == wl_output) {
         wl->scaling = wl->current_output->scale;
+        wl_surface_set_buffer_scale(wl->surface, wl->scaling);
         spawn_cursor(wl);
         set_geometry(wl);
         wl->window_size = wl->vdparams;
@@ -711,6 +712,7 @@ static void surface_handle_enter(void *data, struct wl_surface *wl_surface,
     if (wl->scaling != wl->current_output->scale && wl->vo_opts->hidpi_window_scale) {
         double factor = (double)wl->scaling / wl->current_output->scale;
         wl->scaling = wl->current_output->scale;
+        wl_surface_set_buffer_scale(wl->surface, wl->scaling);
         spawn_cursor(wl);
         rescale_geometry_dimensions(wl, factor);
         wl->pending_vo_events |= VO_EVENT_DPI;