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

url/url.gyp

Index: url/url.gyp
diff --git a/url/url.gyp b/url/url.gyp
index 0ffc51a8c410ecad04934baa5f790deae3c8d9d5..97426603244879f51917e8364c4d44c77f892035 100644
--- a/url/url.gyp
+++ b/url/url.gyp
@@ -54,6 +54,12 @@
             'url_canon_icu_alternatives_android.h',
           ],
         }],
+        ['OS=="mac" or OS=="ios"', {
+          'sources': [
+            'mac/url_conversions.h',
+            'mac/url_conversions.mm',
+          ],
+        }],
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [4267, ],
@@ -94,6 +100,11 @@
             ],
           }
         ],
+        ['OS=="mac" or OS=="ios"', {
+          'sources': [
+            'mac/url_conversions_unittest.mm',
+          ],
+        }],
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [4267, ],