Add GrOpList and rename GrDrawTarget to GrRenderTargetOpList

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3910

Change-Id: I026aa26ecc61a0d002e98892dca728536259e8b1
Reviewed-on: https://skia-review.googlesource.com/3910
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/batches/GrDrawBatch.h b/src/gpu/batches/GrDrawBatch.h
index 5f37b7b..e675f5f 100644
--- a/src/gpu/batches/GrDrawBatch.h
+++ b/src/gpu/batches/GrDrawBatch.h
@@ -42,7 +42,7 @@
 };
 
 /**
- * Base class for GrBatches that draw. These batches have a GrPipeline installed by GrDrawTarget.
+ * Base class for GrBatches that draw. These batches have a GrPipeline installed by GrOpList.
  */
 class GrDrawBatch : public GrBatch {
 public: