Remove SkSurface::MakeFromBackendTexture variant that doesn't take SkColorType

Bug: skia:6718
Change-Id: I8289c54ca9a5f89d10dc0b0dfe750d4fd1da0b64
Reviewed-on: https://skia-review.googlesource.com/115102
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
5 files changed