Reland of add a ClassID function to GrBatch (patchset #1 id:1 of https://codereview.chromium.org/1353043002/ )

Reason for revert:
DEPS roll seems to have landed w/o this revert, so revert it again

Original issue's description:
> Revert of add a ClassID function to GrBatch (patchset #5 id:80001 of https://codereview.chromium.org/1352813003/ )
>
> Reason for revert:
> Speculative revert to unblock DEPS roll
>
> Original issue's description:
> > add a ClassID function to GrBatch
> >
> > BUG=skia:
> >
> > Committed: https://skia.googlesource.com/skia/+/4078d529e9e199eea13456db7bf3a63a104ab5b9
> >
> > Committed: https://skia.googlesource.com/skia/+/eb44d53cf96a7eaf103a98d76079ce1f5495e343
>
> TBR=robertphillips@google.com,bsalomon@google.com,joshualitt@google.com,joshualitt@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/48e3a45ade15c52c0c1a10cb00907dd444897745

TBR=robertphillips@google.com,bsalomon@google.com,joshualitt@google.com,joshualitt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1344373005
diff --git a/src/gpu/GrAtlasTextContext.cpp b/src/gpu/GrAtlasTextContext.cpp
index fa96a8d..822c480 100644
--- a/src/gpu/GrAtlasTextContext.cpp
+++ b/src/gpu/GrAtlasTextContext.cpp
@@ -1431,6 +1431,8 @@
 
 class TextBatch : public GrVertexBatch {
 public:
+    DEFINE_BATCH_CLASS_ID
+
     typedef GrAtlasTextContext::DistanceAdjustTable DistanceAdjustTable;
     typedef GrAtlasTextBlob Blob;
     typedef Blob::Run Run;
@@ -1448,7 +1450,6 @@
                                    GrBatchFontCache* fontCache) {
         TextBatch* batch = new TextBatch;
 
-        batch->initClassID<TextBatch>();
         batch->fFontCache = fontCache;
         switch (maskFormat) {
             case kA8_GrMaskFormat:
@@ -1474,7 +1475,7 @@
                                           SkColor filteredColor, bool isLCD,
                                           bool useBGR) {
         TextBatch* batch = new TextBatch;
-        batch->initClassID<TextBatch>();
+
         batch->fFontCache = fontCache;
         batch->fMaskType = isLCD ? kLCDDistanceField_MaskType : kGrayscaleDistanceField_MaskType;
         batch->fDistanceAdjustTable.reset(SkRef(distanceAdjustTable));
@@ -1783,7 +1784,7 @@
         this->flush(target, &flushInfo);
     }
 
-    TextBatch() {} // initialized in factory functions.
+    TextBatch() : INHERITED(ClassID()) {} // initialized in factory functions.
 
     ~TextBatch() {
         for (int i = 0; i < fGeoCount; i++) {
@@ -2044,6 +2045,8 @@
     // Distance field properties
     SkAutoTUnref<const DistanceAdjustTable> fDistanceAdjustTable;
     SkColor fFilteredColor;
+
+    typedef GrVertexBatch INHERITED;
 };
 
 void GrAtlasTextContext::flushRunAsPaths(GrDrawContext* dc, GrRenderTarget* rt,