Retry proxies which were cached as bad before giving up....

net/http/http_network_transaction.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/http/http_network_transaction.h"
 
 #include "base/format_macros.h"
 #include "base/scoped_ptr.h"
 #include "base/compiler_specific.h"
 #include "base/field_trial.h"
@@ skipping 593 matching lines @@
   //
   // In case (4) it is less obvious what the right thing to do is. On the
   // one hand, for consistency it would be natural to hard-fail as well.
   // However, both Firefox 3.5 and Internet Explorer 8 will silently fall-back
   // to DIRECT in this case, so we will do the same for compatibility.
   //
   // For more information, see:
   // http://www.chromium.org/developers/design-documents/proxy-settings-fallback
 
   if (proxy_info_.is_empty()) {
-    // No proxies/direct to choose from. This can happen when:
-    //   a. We don't support any of the proxies in the returned list.
-    //   b. The proxy service returned us an empty list.
-    //      1. this can happen if all the proxies were marked as bad already.
-    //
-    // TODO(eroman): in case (b.1) it would be better to just try the bad
-    // proxies again rather than failing without having tried anything!
-    return ERR_EMPTY_PROXY_LIST;
+    // No proxies/direct to choose from. This happens when we don't support any
+    // of the proxies in the returned list.
+    return ERR_NO_SUPPORTED_PROXIES;
   }
 
   if (result != OK) {
     DLOG(ERROR) << "Failed to resolve proxy: " << result;
     // Fall-back to direct when there were runtime errors in the PAC script,
     // or some other failure with the settings.
     proxy_info_.UseDirect();
   }
 
   next_state_ = STATE_INIT_CONNECTION;
@@ skipping 1234 matching lines @@
   AuthChallengeInfo* auth_info = new AuthChallengeInfo;
   auth_info->is_proxy = target == HttpAuth::AUTH_PROXY;
   auth_info->host_and_port = ASCIIToWide(GetHostAndPort(auth_origin));
   auth_info->scheme = ASCIIToWide(auth_handler_[target]->scheme());
   // TODO(eroman): decode realm according to RFC 2047.
   auth_info->realm = ASCIIToWide(auth_handler_[target]->realm());
   response_.auth_challenge = auth_info;
 }
 
 }  // namespace net