net: Cleanup class/struct forward declarations

net/base/parse_number.h

 // Copyright 2016 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_PARSE_NUMBER_H_
 #define NET_BASE_PARSE_NUMBER_H_
 
 #include "base/compiler_specific.h"
 #include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 
 // This file contains utility functions for parsing numbers, in the context of
 // network protocols.
 //
 // Q: Doesn't //base already provide these in string_number_conversions.h, with
 //    functions like base::StringToInt()?
 //
 // A: Yes, and those functions are used under the hood by these implementations.
 //
 //    However using the base::StringTo*() has historically led to subtle bugs
 //    in the context of parsing network protocols:
 //
 //      * Permitting a leading '+'
 //      * Incorrectly classifying overflow/underflow from a parsing failure
 //      * Allowing negative numbers for non-negative fields
 //
 //   This API tries to avoid these problems by picking sensible defaults for
 //   //net code. For more details see crbug.com/596523.
 
-class GURL;
-
 namespace net {
 
 // Format to use when parsing integers.
 enum class ParseIntFormat {
   // Accepts non-negative base 10 integers of the form:
   //
   //    1*DIGIT
   //
   // This construction is used in a variety of IETF standards, such as RFC 7230
   // (HTTP).
@@ skipping 64 matching lines @@
     WARN_UNUSED_RESULT;
 
 NET_EXPORT bool ParseUint64(const base::StringPiece& input,
                             uint64_t* output,
                             ParseIntError* optional_error = nullptr)
     WARN_UNUSED_RESULT;
 
 }  // namespace net
 
 #endif  // NET_BASE_PARSE_NUMBER_H_