Keep track of network error in ProxyRetryInfo.

net/base/network_delegate.h

 // 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.
 
 #ifndef NET_BASE_NETWORK_DELEGATE_H_
 #define NET_BASE_NETWORK_DELEGATE_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 50 matching lines @@
   // checking on parameters. See the corresponding virtuals for explanations of
   // the methods and their arguments.
   int NotifyBeforeURLRequest(URLRequest* request,
                              const CompletionCallback& callback,
                              GURL* new_url);
   void NotifyResolveProxy(const GURL& url,
                           int load_flags,
                           const ProxyService& proxy_service,
                           ProxyInfo* result);
   void NotifyProxyFallback(const ProxyServer& bad_proxy,
-                           int net_error,
-                           bool did_fallback);
+                           int net_error);
   int NotifyBeforeSendHeaders(URLRequest* request,
                               const CompletionCallback& callback,
                               HttpRequestHeaders* headers);
   void NotifyBeforeSendProxyHeaders(URLRequest* request,
                                     const ProxyInfo& proxy_info,
                                     HttpRequestHeaders* headers);
   void NotifySendHeaders(URLRequest* request,
                          const HttpRequestHeaders& headers);
   int NotifyHeadersReceived(
       URLRequest* request,
@@ skipping 48 matching lines @@
                                  GURL* new_url);
 
   // Called as the proxy is being resolved for |url|. Allows the delegate to
   // override the proxy resolution decision made by ProxyService. The delegate
   // may override the decision by modifying the ProxyInfo |result|.
   virtual void OnResolveProxy(const GURL& url,
                               int load_flags,
                               const ProxyService& proxy_service,
                               ProxyInfo* result);
 
-  // Called when use of |bad_proxy| fails due to |net_error|. |did_fallback| is
-  // true if the proxy service was able to fallback to another proxy
-  // configuration.
+  // Called when use of |bad_proxy| fails due to |net_error|. |net_error| is
+  // the network error encountered, if any, and OK if the fallback was
+  // for a reason other than network error (eg. a component wants to add the
+  // proxy to the retry list so that it is not used).

[Ryan Sleevi, 2014/08/15 18:02:36]

Great, the overall comments have helped better understand how/when this is used
(which is a point of comments :D)

I think the e.g. can be simplified now

"and OK if the fallback was for a reason other than a network error (e.g. the
proxy service was explicitly directed to skip a proxy)"

[Not at Google. Contact bengr, 2014/08/15 19:56:53]

Done.

   virtual void OnProxyFallback(const ProxyServer& bad_proxy,
-                               int net_error,
-                               bool did_fallback);
+                               int net_error);
 
   // Called right before the HTTP headers are sent. Allows the delegate to
   // read/write |headers| before they get sent out. |callback| and |headers| are
   // valid only until OnCompleted or OnURLRequestDestroyed is called for this
   // request.
   // See OnBeforeURLRequest for return value description. Returns OK by default.
   virtual int OnBeforeSendHeaders(URLRequest* request,
                                   const CompletionCallback& callback,
                                   HttpRequestHeaders* headers);
 
@@ skipping 112 matching lines @@
 
   // Called before a SocketStream tries to connect.
   // See OnBeforeURLRequest for return value description. Returns OK by default.
   virtual int OnBeforeSocketStreamConnect(
       SocketStream* socket, const CompletionCallback& callback);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_DELEGATE_H_