Move textureType() method from GrSurfaceProxy to GrTextureProxy.

Change-Id: I5cf84210132838bdbf95209dc94210483762a450
Reviewed-on: https://skia-review.googlesource.com/c/175998
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
7 files changed