Revert of add a ClassID function to GrBatch

src/gpu/batches/GrDiscardBatch.h

Index: src/gpu/batches/GrDiscardBatch.h
diff --git a/src/gpu/batches/GrDiscardBatch.h b/src/gpu/batches/GrDiscardBatch.h
index c13e7327d7fbf6930e0983f5537c99c7fc59ecea..8a050a7122ca4e0978104574f05bba6476cdf16a 100644
--- a/src/gpu/batches/GrDiscardBatch.h
+++ b/src/gpu/batches/GrDiscardBatch.h
@@ -15,11 +15,9 @@
 
 class GrDiscardBatch final : public GrBatch {
 public:
-    DEFINE_BATCH_CLASS_ID
-
     GrDiscardBatch(GrRenderTarget* rt)
-        : INHERITED(ClassID())
-        , fRenderTarget(rt) {
+        : fRenderTarget(rt) {
+        this->initClassID<GrDiscardBatch>();
         fBounds = SkRect::MakeWH(SkIntToScalar(rt->width()), SkIntToScalar(rt->height()));
     }
 
@@ -45,8 +43,6 @@
     }
 
     GrPendingIOResource<GrRenderTarget, kWrite_GrIOType> fRenderTarget;
-
-    typedef GrBatch INHERITED;
 };
 
 #endif