Hairline batch

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/6eff8701f027016fbb3147412ec2292dcec2b7f5

Review URL: https://codereview.chromium.org/876673002
diff --git a/src/gpu/GrInOrderDrawBuffer.cpp b/src/gpu/GrInOrderDrawBuffer.cpp
index a760dcb..8805711 100644
--- a/src/gpu/GrInOrderDrawBuffer.cpp
+++ b/src/gpu/GrInOrderDrawBuffer.cpp
@@ -473,7 +473,8 @@
 
         // TODO temporary hack
         if (kDrawBatch_Cmd == strip_trace_bit(iter->fType)) {
-            fBatchTarget.flushNext();
+            DrawBatch* db = reinterpret_cast<DrawBatch*>(iter.get());
+            fBatchTarget.flushNext(db->fBatch->numberOfDraws());
             continue;
         }
 
@@ -646,7 +647,9 @@
 
 void GrInOrderDrawBuffer::closeBatch() {
     if (fDrawBatch) {
+        fBatchTarget.resetNumberOfDraws();
         fDrawBatch->execute(this, fPrevState);
+        fDrawBatch->fBatch->setNumberOfDraws(fBatchTarget.numberOfDraws());
         fDrawBatch = NULL;
     }
 }