Linux: allow proxy PAC file configurations that use just a file path without a file:// prefix.

net/proxy/proxy_config_service_linux.cc

 // 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.
 
 #include "net/proxy/proxy_config_service_linux.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #if defined(USE_GCONF)
 #include <gconf/gconf-client.h>
@@ skipping 1427 matching lines @@
     // probably have a gconf/gsettings problem, and so we don't have a valid
     // proxy config.
     return false;
   }
   if (mode == "none") {
     // Specifically specifies no proxy.
     return true;
   }
 
   if (mode == "auto") {
-    // automatic proxy config
+    // Automatic proxy config.
     std::string pac_url_str;
     if (setting_getter_->GetString(SettingGetter::PROXY_AUTOCONF_URL,
                                    &pac_url_str)) {
       if (!pac_url_str.empty()) {
+        // If the PAC URL is actually a file path, then put file:// in front.
+        if (pac_url_str[0] == '/')
+          pac_url_str = "file://" + pac_url_str;
         GURL pac_url(pac_url_str);
         if (!pac_url.is_valid())
           return false;
         config->set_pac_url(pac_url);
         return true;
       }
     }
     config->set_auto_detect(true);
     return true;
   }
@@ skipping 346 matching lines @@
 void ProxyConfigServiceLinux::RemoveObserver(Observer* observer) {
   delegate_->RemoveObserver(observer);
 }
 
 ProxyConfigService::ConfigAvailability
     ProxyConfigServiceLinux::GetLatestProxyConfig(ProxyConfig* config) {
   return delegate_->GetLatestProxyConfig(config);
 }
 
 }  // namespace net