Update a WARNING with a bug URL.

net/proxy/proxy_service.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_service.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <winhttp.h>
 #endif
@@ skipping 336 matching lines @@
     // (because the configuration will never require PAC).
     return new ProxyService(new ProxyConfigServiceFixed(*pi), NULL);
   }
 #if defined(OS_WIN)
   return new ProxyService(new ProxyConfigServiceWin(),
                           new ProxyResolverWinHttp());
 #elif defined(OS_MACOSX)
   return new ProxyService(new ProxyConfigServiceMac(),
                           new ProxyResolverMac());
 #else
-  // This used to be a NOTIMPLEMENTED(), but that logs as an error,
-  // screwing up layout tests.
-  LOG(WARNING) << "Proxies are not implemented; remove me once that's fixed.";
-  // http://code.google.com/p/chromium/issues/detail?id=4523 is the bug
-  // to implement this.
+  // TODO(port): implement ProxyConfigServiceLinux as well as make use of
+  // ProxyResolverV8 once it's implemented.
+  // See:
+  // - http://code.google.com/p/chromium/issues/detail?id=8143
+  // - http://code.google.com/p/chromium/issues/detail?id=2764
   return CreateNull();
 #endif
 }
 
 // static
 ProxyService* ProxyService::CreateNull() {
   // The ProxyResolver is set to NULL, since it should never be called
   // (because the configuration will never require PAC).
   return new ProxyService(new ProxyConfigServiceNull, NULL);
 }
@@ skipping 402 matching lines @@
   }
 }
 
 void SyncProxyServiceHelper::OnCompletion(int rv) {
   result_ = rv;
   event_.Signal();
 }
 
 }  // namespace net