Introduce GrBatch subclasses GrDrawBatch and GrVertexBatch to prepare for non-drawing batches

src/gpu/GrReorderCommandBuilder.cpp

Index: src/gpu/GrReorderCommandBuilder.cpp
diff --git a/src/gpu/GrReorderCommandBuilder.cpp b/src/gpu/GrReorderCommandBuilder.cpp
index 869ae532af7193e1771baa4b9b164bb5178e56c2..f08b7f17d007d596fb69ee8a6594f4c9242ee43a 100644
--- a/src/gpu/GrReorderCommandBuilder.cpp
+++ b/src/gpu/GrReorderCommandBuilder.cpp
@@ -15,7 +15,7 @@ static bool intersect(const Left& a, const Right& b) {
            a.fTop < b.fBottom && b.fTop < a.fBottom;
 }
 
-GrTargetCommands::Cmd* GrReorderCommandBuilder::recordDrawBatch(GrBatch* batch,
+GrTargetCommands::Cmd* GrReorderCommandBuilder::recordDrawBatch(GrDrawBatch* batch,
                                                                 const GrCaps& caps) {
     // Check if there is a Batch Draw we can batch with by linearly searching back until we either
     // 1) check every draw