Introducing a net::GenerateMimeMultipartBoundary helper.

third_party/WebKit/Source/platform/network/FormDataEncoder.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 81 matching lines @@
     if (charset.isEmpty()) {
         if (defaultCharset.isEmpty())
             return WTF::UTF8Encoding();
 
         return defaultCharset;
     }
 
     return charset;
 }
 
+// TODO(lukasza): Reuse net::GenerateMimeMultipartBoundary instead.

[Ryan Sleevi, 2016/01/08 19:55:04]

I would have objected to this TODO - The Blink code shouldn't be pointing at
//net code.

 Vector<char> FormDataEncoder::generateUniqueBoundaryString()
 {
     Vector<char> boundary;
 
     // The RFC 2046 spec says the alphanumeric characters plus the
     // following characters are legal for boundaries:  '()+_,-./:=?
     // However the following characters, though legal, cause some sites
     // to fail: (),./:=+
     // Note that our algorithm makes it twice as much likely for 'A' or 'B'
     // to appear in the boundary string, because 0x41 and 0x42 are present in
@@ skipping 104 matching lines @@
         } else if (c == '\n' || (c == '\r' && (i + 1 >= length || string.data()[i + 1] != '\n'))) {
             append(buffer, "%0D%0A");
         } else if (c != '\r') {
             append(buffer, '%');
             appendByteAsHex(c, buffer);
         }
     }
 }
 
 }