add fsync to try to get complete skps from webpage picture capture

include/core/SkStream.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkStream_DEFINED
 #define SkStream_DEFINED
 
@@ skipping 342 matching lines @@
 public:
     SkFILEWStream(const char path[]);
     virtual ~SkFILEWStream();
 
     /** Returns true if the current path could be opened.
     */
     bool isValid() const { return fFILE != NULL; }
 
     bool write(const void* buffer, size_t size) override;
     void flush() override;
+    void fsync();
     size_t bytesWritten() const override;
 
 private:
     FILE* fFILE;
 
     typedef SkWStream INHERITED;
 };
 
 class SkMemoryWStream : public SkWStream {
 public:
@@ skipping 66 matching lines @@
 
 private:
     size_t fBytesWritten;
     typedef SkWStream INHERITED;
 };
 
 // for now
 typedef SkFILEStream SkURLStream;
 
 #endif