Upstream "nsurl_util.{h,mm}" from Chrome on iOS repository.

net/base/escape.h

 // Copyright (c) 2012 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 NET_BASE_ESCAPE_H_
 #define NET_BASE_ESCAPE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 12 matching lines @@
 // This is basically the same as encodeURIComponent in javascript.
 NET_EXPORT std::string EscapeQueryParamValue(const std::string& text,
                                              bool use_plus);
 
 // Escapes a partial or complete file/pathname.  This includes:
 // non-printable, non-7bit, and (including space)  "#%:<>?[\]^`{|}
 // For the base::string16 version, we attempt a conversion to |codepage| before
 // encoding the string.  If this conversion fails, we return false.
 NET_EXPORT std::string EscapePath(const std::string& path);
 
+// Escapes characters as per expectations of NSURL. This includes:
+// non-printable, non-7bit, and (including space)  "#%<>[\]^`{|}
+NET_EXPORT std::string EscapeNSURLPrecursor(const std::string& precursor);

[mmenke, 2014/12/03 15:30:12]

optional:  Suggest surrounding this in #ifdef OS_MACOSX (That's define on iOS
and OSX, right?).  Not because compiling it elsewhere is the end of the world,
but just to indicate there's no reason to use it eslewhere.

[erikchen, 2014/12/03 18:14:01]

Done.

+
 // Escapes application/x-www-form-urlencoded content.  This includes:
 // non-printable, non-7bit, and (including space)  ?>=<;+'&%$#"![\]^`{|}
 // Space is escaped as + (if use_plus is true) and other special characters
 // as %XX (hex).
 NET_EXPORT std::string EscapeUrlEncodedData(const std::string& path,
                                             bool use_plus);
 
 // Escapes all non-ASCII input.
 NET_EXPORT std::string EscapeNonASCII(const std::string& input);
 
@@ skipping 86 matching lines @@
     UnescapeRule::Type rules,
     base::OffsetAdjuster::Adjustments* adjustments);
 
 // Unescapes the following ampersand character codes from |text|:
 // &lt; &gt; &amp; &quot; &#39;
 NET_EXPORT base::string16 UnescapeForHTML(const base::string16& text);
 
 }  // namespace net
 
 #endif  // NET_BASE_ESCAPE_H_