SkPDF: add drop() virtual to release resources early.

src/pdf/SkPDFStream.h

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPDFStream_DEFINED
@@ skipping 25 matching lines @@
      *  @param stream The data part of the stream.  Will not take ownership.
      */
     explicit SkPDFStream(SkStream* stream) { this->setData(stream); }
 
     virtual ~SkPDFStream();
 
     // The SkPDFObject interface.
     void emitObject(SkWStream* stream,
                     const SkPDFObjNumMap& objNumMap,
                     const SkPDFSubstituteMap& substitutes) const override;
+    void drop() override;
 
 protected:
     /* Create a PDF stream with no data.  The setData method must be called to
      * set the data.
      */
     SkPDFStream() {}
 
     /** Only call this function once. */
     void setData(SkStream* stream);
     void setData(SkData* data) {
         SkMemoryStream memoryStream(data);
         this->setData(&memoryStream);
     }
 
 private:
     SkAutoTDelete<SkStreamRewindable> fCompressedData;
 
     typedef SkPDFDict INHERITED;
 };
 
 #endif