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/vk/GrVkGpu.cpp b/src/gpu/vk/GrVkGpu.cpp
index 0eb8241..b13e162 100644
--- a/src/gpu/vk/GrVkGpu.cpp
+++ b/src/gpu/vk/GrVkGpu.cpp
@@ -1323,7 +1323,7 @@
                                        barrier);
 }
 
-void GrVkGpu::finishDrawTarget() {
+void GrVkGpu::finishOpList() {
     // Submit the current command buffer to the Queue
     this->submitCommandBuffer(kSkip_SyncQueue);
 }