Revert "Revert "Create GrXferProcessor while doing GrProcessorSet analysis.""

This reverts commit 5dac9b3b5bf7e9c06c207cb92e257535c7d9ec95.

Bug: skia:
Change-Id: I3db2ec6776eb10c1f863b3992a2c8048c54b130f
Reviewed-on: https://skia-review.googlesource.com/12620
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
17 files changed