tree fd488e5e82c262c5576655297e74b21ed16161e3
parent 766e05b70c5d689d193fba3de7d1239a00eb82e4
author Yilong Li <liyl@google.com> 1601685643 -0700
committer Yilong Li <liyl@google.com> 1601685643 -0700

MVKImage: Check plane count in IOSurface only if it has chroma subsampling.

useIOSurface() sets the plane information in IOSurface only if
the image format has chroma subsampling. And when we import an
IOSurface, we should only check count of planes when the format
has chroma subsampling.

This resolves a crash in the following case to let two VkImages
share the same IOSurface:

```
VkImage image1, image2;

// the format in |info| is a non-chroma-subsampling format,
// e.g. R8G8B8A8_UNORM.
vkCreateImage(info, &image1);
vkCreateImage(info, &image2);

IOSurfaceRef ioSurface;
vkUseIOSurfaceMVK(image1, nil);
vkGetIOSurfaceMVK(image1, &ioSurface);
vkUseIOSurfaceMVK(image2, ioSurface);
```