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

net/base/escape.cc

Index: net/base/escape.cc
diff --git a/net/base/escape.cc b/net/base/escape.cc
index 7a068f87ee571ce555d5f063b7a0101ef280d1de..63e5be9e3391165cd4ea5e54153349b848d7a0d2 100644
--- a/net/base/escape.cc
+++ b/net/base/escape.cc
@@ -318,6 +318,12 @@ static const Charmap kPathCharmap = {{
   0xffffffffL, 0xffffffffL, 0xffffffffL, 0xffffffffL
 }};
 
+// non-printable, non-7bit, and (including space)  "#%<>[\]^`{|}
+static const Charmap kNSURLCharmap = {{
+  0xffffffffL, 0x5000002dL, 0x78000000L, 0xb8000001L,
+  0xffffffffL, 0xffffffffL, 0xffffffffL, 0xffffffffL
+}};
+
 // non-printable, non-7bit, and (including space) ?>=<;+'&%$#"![\]^`{|}
 static const Charmap kUrlEscape = {{
   0xffffffffL, 0xf80008fdL, 0x78000001L, 0xb8000001L,
@@ -347,6 +353,10 @@ std::string EscapePath(const std::string& path) {
   return Escape(path, kPathCharmap, false);
 }
 
+std::string EscapeNSURLPrecursor(const std::string& precursor) {
+  return Escape(precursor, kNSURLCharmap, false, true);
+}
+
 std::string EscapeUrlEncodedData(const std::string& path, bool use_plus) {
   return Escape(path, kUrlEscape, use_plus);
 }