Remove the SkCanvas comment API

src/core/SkPictureRecord.h

Index: src/core/SkPictureRecord.h
diff --git a/src/core/SkPictureRecord.h b/src/core/SkPictureRecord.h
index af65013b55fea993ad1d4e2fa7a8d48f24577de9..2aeb69dcd499ff1d37aa30783799272a47a3153f 100644
--- a/src/core/SkPictureRecord.h
+++ b/src/core/SkPictureRecord.h
@@ -29,10 +29,6 @@ public:
     SkPictureRecord(const SkISize& dimensions, uint32_t recordFlags);
     virtual ~SkPictureRecord();
 
-    void beginCommentGroup(const char* description) override;
-    void addComment(const char* kywd, const char* value) override;
-    void endCommentGroup() override;
-
     const SkTDArray<const SkPicture* >& getPictureRefs() const {
         return fPictureRefs;
     }