Allow url::SchemeHostPort to hold non-file scheme without port

url/scheme_host_port.h

 // Copyright 2015 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 URL_SCHEME_HOST_PORT_H_
 #define URL_SCHEME_HOST_PORT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 18 matching lines @@
 // It may, however, be inappropriate to use as a cache key for persistent
 // storage associated with a host.
 //
 // In particular, note that:
 //
 // * SchemeHostPort can only represent schemes which follow the RFC 3986 syntax
 //   (e.g. those registered with GURL as "standard schemes"). Non-standard
 //   schemes such as "blob", "filesystem", "data", and "javascript" can only be
 //   represented as invalid SchemeHostPort objects.
 //
-// * The "file" scheme follows the standard syntax, but it is important to note
-//   that the authority portion (host, port) is optional. URLs without an
-//   authority portion will be represented with an empty string for the host,
-//   and a port of 0 (e.g. "file:///etc/hosts" => ("file", "", 0)), and URLs
-//   with a host-only authority portion will be represented with a port of 0
-//   (e.g. "file://example.com/etc/hosts" => ("file", "example.com", 0)). See
-//   Section 3 of RFC 3986 to better understand these constructs.
+// * For example, the "file" scheme follows the standard syntax, but it is
+//   important to note that the authority portion (host, port) is optional.
+//   URLs without an authority portion will be represented with an empty string
+//   for the host, and a port of 0 (e.g. "file:///etc/hosts" =>
+//   ("file", "", 0)), and URLs with a host-only authority portion will be
+//   represented with a port of 0 (e.g. "file://example.com/etc/hosts" =>
+//   ("file", "example.com", 0)). See Section 3 of RFC 3986 to better understand
+//   these constructs.
 //
 // * SchemeHostPort has no notion of the Origin concept (RFC 6454), and in
 //   particular, it has no notion of a "unique" Origin. If you need to take
 //   uniqueness into account (and, if you're making security-relevant decisions
-//   then you absolutely do), please use 'url::Origin' instead[1].
-//
-// [1]: // TODO(mkwst): Land 'url::Origin'. :)
+//   then you absolutely do), please use 'url::Origin' instead.
 //
 // Usage:
 //
 // * SchemeHostPort objects are commonly created from GURL objects:
 //
 //     GURL url("https://example.com/");
 //     url::SchemeHostPort tuple(url);
 //     tuple.scheme(); // "https"
 //     tuple.host(); // "example.com"
 //     tuple.port(); // 443
@@ skipping 60 matching lines @@
 
  private:
   std::string scheme_;
   std::string host_;
   uint16 port_;
 };
 
 }  // namespace url
 
 #endif  // URL_SCHEME_HOST_PORT_H_