net: add IsMethodIdempotent() to HttpUtil

net/http/http_util.cc

 // 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.
 
 // The rules for parsing content-types were borrowed from Firefox:
 // http://lxr.mozilla.org/mozilla/source/netwerk/base/src/nsURLHelper.cpp#834
 
 #include "net/http/http_util.h"
 
 #include <algorithm>
@@ skipping 333 matching lines @@
 
 }  // namespace
 
 // static
 bool HttpUtil::IsMethodSafe(const std::string& method) {
   return method == "GET" || method == "HEAD" || method == "OPTIONS" ||
          method == "TRACE";
 }
 
 // static
+bool HttpUtil::IsMethodIdempotent(const std::string& method) {
+  return IsMethodSafe(method) || method == "PUT" || method == "DELETE";
+}
+
+// static
 bool HttpUtil::IsSafeHeader(const std::string& name) {
   std::string lower_name(base::ToLowerASCII(name));
   if (base::StartsWith(lower_name, "proxy-", base::CompareCase::SENSITIVE) ||
       base::StartsWith(lower_name, "sec-", base::CompareCase::SENSITIVE))
     return false;
 
   for (const char* field : kForbiddenHeaderFields) {
     if (lower_name == field)
       return false;
   }
@@ skipping 789 matching lines @@
   while (encoding_tokenizer.GetNext()) {
     base::StringPiece encoding = TrimLWS(encoding_tokenizer.token_piece());
     if (encoding.find_first_of(HTTP_LWS) != base::StringPiece::npos)
       return false;
     used_encodings->insert(base::ToLowerASCII(encoding));
   }
   return true;
 }
 
 }  // namespace net