Make GrPipeline non-refcounted

GrPipelines are now created in GrOpFlushState's arena during GrOp::prepare() and cleaned up when the arena is destroyed.

Change-Id: I2cc4f03ce130bfb22e9d28bb3c22c485113d5d53
Reviewed-on: https://skia-review.googlesource.com/24681
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed