Don't add default Accept-Language and Accept-Charset headers if specific ones...

net/url_request/url_request_http_job.cc

 // Copyright (c) 2006-2009 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.
 
 #include "net/url_request/url_request_http_job.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/file_util.h"
@@ skipping 569 matching lines @@
   } else {
     rv = net::ERR_FAILED;
   }
 
   // The transaction started synchronously, but we need to notify the
   // URLRequest delegate via the message loop.
   MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
       this, &URLRequestHttpJob::OnStartCompleted, rv));
 }
 
+// Helper. If |*headers| already contains |header_name| do nothing,
+// otherwise add <header_name> ": " <header_value> to the end of the list.
+static void AppendHeaderIfMissing(const char* header_name,
+                                  const std::string& header_value,
+                                  std::string* headers) {
+  if (header_value.empty())
+    return;
+  if (net::HttpUtil::HasHeader(*headers, header_name))
+    return;
+  *headers += std::string(header_name) + ": " + header_value + "\r\n";
+}
+
 void URLRequestHttpJob::AddExtraHeaders() {
   // TODO(jar): Consider optimizing away SDCH advertising bytes when the URL is
   // probably an img or such (and SDCH encoding is not likely).
   bool advertise_sdch = SdchManager::Global() &&
       SdchManager::Global()->IsInSupportedDomain(request_->url());
   std::string avail_dictionaries;
   if (advertise_sdch) {
     SdchManager::Global()->GetAvailDictionaryList(request_->url(),
                                                   &avail_dictionaries);
 
@@ skipping 36 matching lines @@
       // a response.  When done, we'll record histograms via SDCH_DECODE or
       // SDCH_PASSTHROUGH.  Hence we need to record packet arrival times.
       EnablePacketCounting(kSdchPacketHistogramCount);
     }
   }
 
   URLRequestContext* context = request_->context();
   if (context) {
     if (context->AllowSendingCookies(request_))
       request_info_.extra_headers += AssembleRequestCookies();
-    if (!context->accept_language().empty())
-      request_info_.extra_headers += "Accept-Language: " +
-          context->accept_language() + "\r\n";
-    if (!context->accept_charset().empty())
-      request_info_.extra_headers += "Accept-Charset: " +
-          context->accept_charset() + "\r\n";
+
+    // Only add default Accept-Language and Accept-Charset if the request
+    // didn't have them specifically specified.

[eroman, 2009/09/24 02:19:32]

nit: slightly redundant wording; can probably omit "specifically".

+    AppendHeaderIfMissing("Accept-Language",
+                          context->accept_language(),
+                          &request_info_.extra_headers);
+    AppendHeaderIfMissing("Accept-Charset",
+                          context->accept_charset(),
+                          &request_info_.extra_headers);
   }
 }
 
 std::string URLRequestHttpJob::AssembleRequestCookies() {
   if (request_info_.load_flags & net::LOAD_DO_NOT_SEND_COOKIES)
     return std::string();
 
   URLRequestContext* context = request_->context();
   if (context) {
     // Add in the cookie header.  TODO might we need more than one header?
@@ skipping 42 matching lines @@
 
   std::string name = "Strict-Transport-Security";
   std::string value;
 
   void* iter = NULL;
   while (response_info_->headers->EnumerateHeader(&iter, name, &value)) {
     ctx->strict_transport_security_state()->DidReceiveHeader(
         request_info_.url, value);
   }
 }