add a ClassID function to GrBatch

src/gpu/batches/GrDrawPathBatch.h

Index: src/gpu/batches/GrDrawPathBatch.h
diff --git a/src/gpu/batches/GrDrawPathBatch.h b/src/gpu/batches/GrDrawPathBatch.h
index 71ef9d42b482de9dc5f5002c986162011fb894ed..8f4df03ff79e6ccd9e7946a4320677e9d5539a88 100644
--- a/src/gpu/batches/GrDrawPathBatch.h
+++ b/src/gpu/batches/GrDrawPathBatch.h
@@ -19,6 +19,8 @@
 
 class GrDrawPathBatchBase : public GrDrawBatch {
 public:
+    BATCH_CLASS_ID
+
     void getInvariantOutputColor(GrInitInvariantOutput* out) const override {
         out->setKnownFourComponents(fColor);
     }
@@ -153,6 +155,8 @@ public:
         return SkNEW_ARGS(GrDrawPathRangeBatch, (viewMatrix, localMatrix, color, pathRangeDraw));
     }
 
+    BATCH_CLASS_ID
+
     ~GrDrawPathRangeBatch() override;
 
     const char* name() const override { return "DrawPathRange"; }