SkPDF: Hold page objects, not SkPDFDevices.

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"
 #include "SkPDFMetadata.h"
-#include "SkPDFTypes.h"
+#include "SkPDFFont.h"
 
 class SkPDFDevice;
 
 sk_sp<SkDocument> SkPDFMakeDocument(
         SkWStream* stream,
         void (*doneProc)(SkWStream*, bool),
         SkScalar rasterDpi,
         SkPixelSerializer* jpegEncoder);
 
 // Logically part of SkPDFDocument (like SkPDFCanon), but separate to
@@ skipping 42 matching lines @@
        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; }
 
 private:
     SkPDFObjectSerializer fObjectSerializer;
     SkPDFCanon fCanon;
-    SkTArray<sk_sp<const SkPDFDevice>> fPageDevices;
+    SkPDFGlyphSetMap fGlyphUsage;
+    SkTArray<sk_sp<SkPDFDict>> fPages;
+    sk_sp<SkPDFDict> fDests;
+    sk_sp<SkPDFDevice> fPageDevice;
     sk_sp<SkCanvas> fCanvas;
     SkScalar fRasterDpi;
     SkPDFMetadata fMetadata;
 };
 
 #endif  // SkPDFDocument_DEFINED