Revert "Always make SkImageShaders in heap."

This reverts commit ff590a12441002d281254ec6a86070ac0a19263f.

Reason for revert: This breaks the android roll because they are using
a private call. Updating android tests to use new api.

Original change's description:
> Always make SkImageShaders in heap.
> 
> I made a couple of measurments, and it looks like any differences is
> well below the noise threshold.
> 
> Just for the record run1: .9991 of baseline and run2 .9988 of baseline.
> I was using top25 .skps as workload.
> 
> TBR=mtklein@google.com
> 
> Change-Id: If4fa06e5d5df72fb67dbb4bbb99c926f05765897
> Reviewed-on: https://skia-review.googlesource.com/8341
> Reviewed-by: Herb Derby <herb@google.com>
> Commit-Queue: Herb Derby <herb@google.com>
> 

TBR=mtklein@chromium.org,mtklein@google.com,herb@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: Ibdaafc796702e250933b62e5f4abb5e2ce8d40c0
Reviewed-on: https://skia-review.googlesource.com/8393
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Herb Derby <herb@google.com>
8 files changed