Remove the SkCanvas comment API

src/core/SkRecorder.h

Index: src/core/SkRecorder.h
diff --git a/src/core/SkRecorder.h b/src/core/SkRecorder.h
index b6f153dc54824f533f6a4b0de1ab61f4302b5268..7fab62d0236a0bd45f7f3672d02fea8f5724b14c 100644
--- a/src/core/SkRecorder.h
+++ b/src/core/SkRecorder.h
@@ -116,10 +116,6 @@ public:
 
     void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*) override;
 
-    void beginCommentGroup(const char*) override;
-    void addComment(const char*, const char*) override;
-    void endCommentGroup() override;
-
     SkSurface* onNewSurface(const SkImageInfo&, const SkSurfaceProps&) override { return NULL; }
 
     void flushMiniRecorder();