add a ClassID function to GrBatch

src/gpu/batches/GrAAHairLinePathRenderer.cpp

Index: src/gpu/batches/GrAAHairLinePathRenderer.cpp
diff --git a/src/gpu/batches/GrAAHairLinePathRenderer.cpp b/src/gpu/batches/GrAAHairLinePathRenderer.cpp
index c6bdd055bb9eccb8bbdbc8cb98416745984e7fe1..1b546d63c1ef445a7e91f2af3857cc9f92a398be 100644
--- a/src/gpu/batches/GrAAHairLinePathRenderer.cpp
+++ b/src/gpu/batches/GrAAHairLinePathRenderer.cpp
@@ -680,6 +680,8 @@ public:
         SkIRect fDevClipBounds;
     };
 
+    BATCH_CLASS_ID
+
     static GrDrawBatch* Create(const Geometry& geometry) { return new AAHairlineBatch(geometry); }
 
     const char* name() const override { return "AAHairlineBatch"; }