SkNonCopyable should be used with private inheritance.

src/pdf/SkPDFFont.h

Index: src/pdf/SkPDFFont.h
diff --git a/src/pdf/SkPDFFont.h b/src/pdf/SkPDFFont.h
index 694c69ac39823e57120e75d50425cef1daf8e627..68a00f079a2d2e7c029d1f4d984f61d2e7bd5a45 100644
--- a/src/pdf/SkPDFFont.h
+++ b/src/pdf/SkPDFFont.h
@@ -21,7 +21,7 @@ class SkPaint;
 class SkPDFCatalog;
 class SkPDFFont;
 
-class SkPDFGlyphSet : public SkNoncopyable {
+class SkPDFGlyphSet : SkNoncopyable {
 public:
     SkPDFGlyphSet();
 
@@ -34,7 +34,7 @@ private:
     SkBitSet fBitSet;
 };
 
-class SkPDFGlyphSetMap : public SkNoncopyable {
+class SkPDFGlyphSetMap : SkNoncopyable {
 public:
     struct FontGlyphSetPair {
         FontGlyphSetPair(SkPDFFont* font, SkPDFGlyphSet* glyphSet);