message: Handle surface size changes in Metal
diff: @@ -79,8 +79,14 @@ id<MTLTexture> acquireDrawable(MetalContext* context) {
  id<MTLTexture> acquireDepthTexture(MetalContext* context) {
  if (context->currentDepthTexture) {
  + // If the surface size has changed, we'll need to allocate a new depth texture.
  + if (context->currentDepthTexture.width != context->currentSurface->surfaceWidth ||
  + context->currentDepthTexture.height != context->currentSurface->surfaceHeight) {
  + context->currentDepthTexture = nil;
  + } else {
  return context->currentDepthTexture;
  }
  + }
  const MTLPixelFormat depthFormat =
  #if defined(IOS)
  