Pass in actual sampled texture and sample params to gpu uniform builders.

To support external textures vulkan needs to know the actual sampler it
will use at pipeline creation time. Thus we need access to the actual
vkimage and sampler state to know how to make these samplers early.

Bug: skia:
Change-Id: I8492bb283932d6800dbfcc8bc86b3bba947397fe
Reviewed-on: https://skia-review.googlesource.com/c/166281
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
25 files changed