gsk: Avoid reuploading textures too much

When filtering changes for an already-cached
texture, we need to clear the render data
before setting the new one, otherwise it
does not take and we end up reuploading
the texture every frame.

gsk/gl/gskgldriver.c

@@ -777,6 +777,8 @@ gsk_gl_driver_load_texture (GskGLDriver *self,
 
   g_hash_table_insert (self->textures, GUINT_TO_POINTER (texture_id), t);
 
+  gdk_texture_clear_render_data (texture);
+
   if (gdk_texture_set_render_data (texture, self, t, gsk_gl_texture_destroyed))
     t->user = texture;