tests/wayland-test-clients: Remove unused create_shm_buffer

We moved the last user of `create_shm_buffer` and can now get rid of it.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3350>

src/tests/wayland-test-clients/wayland-test-client-utils.c

@@ -459,83 +459,6 @@ wayland_display_init (WaylandDisplay *display)
 {
 }
 
-static void
-handle_buffer_release (void             *data,
-                       struct wl_buffer *buffer)
-{
-  wl_buffer_destroy (buffer);
-}
-
-static const struct wl_buffer_listener buffer_listener = {
-  handle_buffer_release
-};
-
-gboolean
-create_shm_buffer (WaylandDisplay    *display,
-                   int                width,
-                   int                height,
-                   struct wl_buffer **out_buffer,
-                   void             **out_data,
-                   int               *out_size)
-{
-  struct wl_shm_pool *pool;
-  static struct wl_buffer *buffer;
-  int fd, size, stride;
-  int bytes_per_pixel;
-  void *data;
-
-  bytes_per_pixel = 4;
-  stride = width * bytes_per_pixel;
-  size = stride * height;
-
-  fd = create_anonymous_file (size);
-  if (fd < 0)
-    {
-      fprintf (stderr, "Creating a buffer file for %d B failed: %m\n",
-               size);
-      return FALSE;
-    }
-
-  data = mmap (NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-  if (data == MAP_FAILED)
-    {
-      fprintf (stderr, "mmap failed: %m\n");
-      close (fd);
-      return FALSE;
-    }
-
-  pool = wl_shm_create_pool (display->shm, fd, size);
-  buffer = wl_shm_pool_create_buffer (pool, 0,
-                                      width, height,
-                                      stride,
-                                      WL_SHM_FORMAT_ARGB8888);
-  wl_buffer_add_listener (buffer, &buffer_listener, buffer);
-  wl_shm_pool_destroy (pool);
-  close (fd);
-
-  *out_buffer = buffer;
-  *out_data = data;
-  *out_size = size;
-
-  return TRUE;
-}
-
-static void
-fill (void    *buffer_data,
-      int      width,
-      int      height,
-      uint32_t color)
-{
-  uint32_t *pixels = buffer_data;
-  int x, y;
-
-  for (y = 0; y < height; y++)
-    {
-      for (x = 0; x < width; x++)
-        pixels[y * width + x] = color;
-    }
-}
-
 void
 draw_surface (WaylandDisplay    *display,
               struct wl_surface *surface,

src/tests/wayland-test-clients/wayland-test-client-utils.h

@@ -99,13 +99,6 @@ WaylandSurface * wayland_surface_new (WaylandDisplay *display,
                                       int             default_height,
                                       uint32_t        color);
 
-gboolean create_shm_buffer (WaylandDisplay    *display,
-                            int                width,
-                            int                height,
-                            struct wl_buffer **out_buffer,
-                            void             **out_data,
-                            int               *out_size);
-
 void draw_surface (WaylandDisplay    *display,
                    struct wl_surface *surface,
                    int                width,