Create GrDraw and start fast pathing src over rects

src/gpu/batches/GrTInstanceBatch.h

Index: src/gpu/batches/GrTInstanceBatch.h
diff --git a/src/gpu/batches/GrTInstanceBatch.h b/src/gpu/batches/GrTInstanceBatch.h
index b4bc0c084f903b62756025db077bef2cc0c2d0dc..9640209c425607fe83308c9c54ca3f7a3fd56d37 100644
--- a/src/gpu/batches/GrTInstanceBatch.h
+++ b/src/gpu/batches/GrTInstanceBatch.h
@@ -77,6 +77,18 @@ public:
         Impl::UpdateBoundsAfterAppend(geo, &fBounds);
     }
 
+    bool appendIfPossible(const Geometry& geo) {
+        const Geometry& mine = fGeoData.back();
+        if (Impl::CanCombine(mine, geo, fOpts)) {
+            fGeoData.push_back(geo);
+            this->updateBoundsAfterAppend();
+            return true;
+        } else {
+            return false;
+        }
+
+    }
+
 private:
     GrTInstanceBatch() : INHERITED(ClassID()) {}