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

src/ports/SkOSFile_stdio.cpp

 /*
  * 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.
  */
 
 #include "SkOSFile.h"
 #include "SkTypes.h"
 
@@ skipping 125 matching lines @@
 size_t sk_fwrite(const void* buffer, size_t byteCount, FILE* f) {
     SkASSERT(f);
     return ::fwrite(buffer, 1, byteCount, f);
 }
 
 void sk_fflush(FILE* f) {
     SkASSERT(f);
     ::fflush(f);
 }
 
+void sk_fsync(FILE* f) {
+#if !defined(_WIN32) && !defined(SK_BUILD_FOR_ANDROID) && !defined(__UCLIBC__) \
+        && !defined(_NEWLIB_VERSION)
+    int fd = ::fileno(f);
+    ::fsync(fd);
+#endif
+}
+
 bool sk_fseek(FILE* f, size_t byteCount) {
     int err = ::fseek(f, (long)byteCount, SEEK_SET);
     return err == 0;
 }
 
 bool sk_fmove(FILE* f, long byteCount) {
     int err = ::fseek(f, byteCount, SEEK_CUR);
     return err == 0;
 }
 
@@ skipping 35 matching lines @@
 #else
     retval = mkdir(path, 0777);
 #endif
     if (0 == retval) {
         return true;
     } else {
         fprintf(stderr, "sk_mkdir: error %d creating dir '%s'\n", errno, path);
         return false;
     }
 }