Base: WritePlatformFile now retries the operation if

base/platform_file.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_PLATFORM_FILE_H_
 #define BASE_PLATFORM_FILE_H_
 #pragma once
 
 #include "build/build_config.h"
 #if defined(OS_WIN)
@@ skipping 105 matching lines @@
 // Closes a file handle. Returns |true| on success and |false| otherwise.
 BASE_EXPORT bool ClosePlatformFile(PlatformFile file);
 
 // Reads the given number of bytes (or until EOF is reached) starting with the
 // given offset. Returns the number of bytes read, or -1 on error.
 BASE_EXPORT int ReadPlatformFile(PlatformFile file, int64 offset,
                                  char* data, int size);
 
 // Writes the given buffer into the file at the given offset, overwritting any
 // data that was previously there. Returns the number of bytes written, or -1
-// on error.
+// on error. Note that this function makes a best effort to write all data on
+// all platforms.
 BASE_EXPORT int WritePlatformFile(PlatformFile file, int64 offset,
                                   const char* data, int size);
 
 // Truncates the given file to the given length. If |length| is greater than
 // the current size of the file, the file is extended with zeros. If the file
 // doesn't exist, |false| is returned.
 BASE_EXPORT bool TruncatePlatformFile(PlatformFile file, int64 length);
 
 // Flushes the buffers of the given file.
 BASE_EXPORT bool FlushPlatformFile(PlatformFile file);
@@ skipping 40 matching lines @@
     return temp;
   }
 
  private:
   PlatformFile* value_;
 };
 
 }  // namespace base
 
 #endif  // BASE_PLATFORM_FILE_H_