Revert "Remove GrPipeline from GrDrawOp."

This reverts commit 2bf4b3a97b770811d9e0558dbbfbdb57cfafbdb7.

Reason for revert: nanobench assertion

Original change's description:
> Remove GrPipeline from GrDrawOp.
> 
> GrDrawOp subclasses are now free to construct their pipelines at flush time and now in theory could use multiple GrPipelines for multipass rendering.
> 
> GrProcessorSet may be used to retain the processors from a GrPaint with "pending execution" style refs.
> 
> NVPR and Instanced rendering are updated to create their pipelines at flush time without a GrPipelineBuilder.
> 
> The monolithic pipeline creation/management that was on GrDrawOp is moved to GrMeshDrawOp. However, this is temporary and will be removed in coming changes.
> 
> Change-Id: I124282e3cea5d070970b5460c8a679fcaf7a8eff
> Reviewed-on: https://skia-review.googlesource.com/7279
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> 

TBR=bsalomon@google.com,robertphillips@google.com,csmartdalton@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I1bc64f6cbbd5f482417637a034342c2b5371dc5c
Reviewed-on: https://skia-review.googlesource.com/9817
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/gpu/GrProgramElement.h b/include/gpu/GrProgramElement.h
index 2538680302..0e065c231f 100644
--- a/include/gpu/GrProgramElement.h
+++ b/include/gpu/GrProgramElement.h
@@ -84,6 +84,7 @@ protected:
 
     void addPendingExecution() const {
         this->validate();
+        SkASSERT(fRefCnt > 0);
         if (0 == fPendingExecutions) {
             static_cast<const DERIVED*>(this)->addPendingIOs();
         }