SkPDF: Glyph Useage Map improvements

src/pdf/SkPDFDocument.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkPDFDocument_DEFINED
 #define SkPDFDocument_DEFINED
 
 #include "SkDocument.h"
@@ skipping 57 matching lines @@
        to the SkPDFObjNumMap without serializing them, they will be
        serialized as well.
 
        It might go without saying that objects should not be changed
        after calling serialize, since those changes will be too late.
        The same goes for changes to the SkPDFSubstituteMap that effect
        the object or its dependencies.
      */
     void serialize(const sk_sp<SkPDFObject>&);
     SkPDFCanon* canon() { return &fCanon; }
+    SkPDFGlyphSetMap* getGlyphUsage() { return &fGlyphUsage; }
 
 private:
     SkPDFObjectSerializer fObjectSerializer;
     SkPDFCanon fCanon;
     SkPDFGlyphSetMap fGlyphUsage;
     SkTArray<sk_sp<SkPDFDict>> fPages;
     sk_sp<SkPDFDict> fDests;
     sk_sp<SkPDFDevice> fPageDevice;
     sk_sp<SkCanvas> fCanvas;
     sk_sp<SkPDFObject> fID;
     sk_sp<SkPDFObject> fXMP;
     SkScalar fRasterDpi;
     SkDocument::PDFMetadata fMetadata;
     bool fPDFA;
 };
 
 #endif  // SkPDFDocument_DEFINED