This change implements the performance recommendation from: ...

net/proxy/proxy_resolver_winhttp.cc

 // Copyright (c) 2006-2008 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/proxy/proxy_resolver_winhttp.h"
 
 #include <windows.h>
 #include <winhttp.h>
 
 #include "base/histogram.h"
@@ skipping 72 matching lines @@
   if (!session_handle_ && !OpenWinHttpSession())
     return ERR_FAILED;
 
   // If we have been given an empty PAC url, then use auto-detection.
   //
   // NOTE: We just use DNS-based auto-detection here like Firefox.  We do this
   // to avoid WinHTTP's auto-detection code, which while more featureful (it
   // supports DHCP based auto-detection) also appears to have issues.
   //
   WINHTTP_AUTOPROXY_OPTIONS options = {0};
-  options.fAutoLogonIfChallenged = TRUE;
+  options.fAutoLogonIfChallenged = FALSE;
   options.dwFlags = WINHTTP_AUTOPROXY_CONFIG_URL;
   std::wstring pac_url_wide = ASCIIToWide(pac_url);
   options.lpszAutoConfigUrl =
       pac_url_wide.empty() ? L"http://wpad/wpad.dat" : pac_url_wide.c_str();
 
   WINHTTP_PROXY_INFO info = {0};
   DCHECK(session_handle_);
-  if (!CallWinHttpGetProxyForUrl(
-          session_handle_, ASCIIToWide(query_url).c_str(), &options, &info)) {
+
+  // Per http://msdn.microsoft.com/en-us/library/aa383153(VS.85).aspx, it is
+  // necessary to first try resolving with fAutoLogonIfChallenged set to false.
+  // Otherwise, we failover to trying it with a value of true.  This way we get

[wtc, 2008/09/09 19:03:10]

Nit: "fail over", two words.

+  // good performance in the case where WinHTTP uses an out-of-proc resolver.

[wtc, 2008/09/09 19:03:10]

Nit: "out-of-process"

+  // This is important for Vista and Win2k3.
+  BOOL ok = CallWinHttpGetProxyForUrl(
+      session_handle_, ASCIIToWide(query_url).c_str(), &options, &info);
+  if (!ok) {
     DWORD error = GetLastError();
     LOG(ERROR) << "WinHttpGetProxyForUrl failed: " << error;
-
-    // If we got here because of RPC timeout during out of process PAC
-    // resolution, no further requests on this session are going to work.
-    if ((ERROR_WINHTTP_TIMEOUT == error) ||
-        (ERROR_WINHTTP_AUTO_PROXY_SERVICE_ERROR == error)) {
-      CloseWinHttpSession();
+    if (ERROR_WINHTTP_LOGIN_FAILURE == error) {
+      options.fAutoLogonIfChallenged = TRUE;
+      ok = CallWinHttpGetProxyForUrl(
+          session_handle_, ASCIIToWide(query_url).c_str(), &options, &info);
+      if (!ok) {
+        error = GetLastError();
+        LOG(ERROR) << "WinHttpGetProxyForUrl failed: " << error;

[Nicolas Sylvain, 2008/09/09 15:18:12]

Can you put this line in the other "if (!ok)" under, because right now it will
log an error only if the first error was ERROR_WINHTTP_LOGIN_FAILURE. I think we
should remove this "if(!ok)" completely and just fallback on the other one.

+      }
     }
-
-    return ERR_FAILED;  // TODO(darin): Bug 1189288: translate error code.
+    if(!ok) {
+      // If we got here because of RPC timeout during out of process PAC
+      // resolution, no further requests on this session are going to work.
+      if (ERROR_WINHTTP_TIMEOUT == error ||
+          ERROR_WINHTTP_AUTO_PROXY_SERVICE_ERROR == error) {
+        CloseWinHttpSession();
+      }
+      return ERR_FAILED;  // TODO(darin): Bug 1189288: translate error code.
+    }
   }
 
   int rv = OK;
 
   switch (info.dwAccessType) {
     case WINHTTP_ACCESS_TYPE_NO_PROXY:
       results->UseDirect();
       break;
     case WINHTTP_ACCESS_TYPE_NAMED_PROXY:
       results->UseNamedProxy(WideToASCII(info.lpszProxy));
@@ skipping 29 matching lines @@
 
 void ProxyResolverWinHttp::CloseWinHttpSession() {
   if (session_handle_) {
     WinHttpCloseHandle(session_handle_);
     session_handle_ = NULL;
   }
 }
 
 }  // namespace net