Fix iOS build for XCode 4.6.

chrome/browser/net/proxy_service_factory.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 "chrome/browser/net/proxy_service_factory.h"
 
 #include "base/command_line.h"
 #include "base/string_number_conversions.h"
 #include "base/threading/thread.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 88 matching lines @@
 
     // Parse the switch (it should be a positive integer formatted as decimal).
     int n;
     if (base::StringToInt(s, &n) && n > 0) {
       num_pac_threads = static_cast<size_t>(n);
     } else {
       LOG(ERROR) << "Invalid switch for number of PAC threads: " << s;
     }
   }
 
-  net::ProxyService* proxy_service;
+  net::ProxyService* proxy_service = NULL;
   if (use_v8) {
 #if defined(OS_IOS)
     NOTREACHED();
 #else
     net::DhcpProxyScriptFetcherFactory dhcp_factory;
     if (command_line.HasSwitch(switches::kDisableDhcpWpad)) {
       dhcp_factory.set_enabled(false);
     }
 
     proxy_service = net::CreateProxyServiceUsingV8ProxyResolver(
         proxy_config_service,
         num_pac_threads,
         new net::ProxyScriptFetcherImpl(context),
         dhcp_factory.Create(context),
         context->host_resolver(),
         net_log,
         context->network_delegate());
 #endif  // defined(OS_IOS)
   } else {
     proxy_service = net::ProxyService::CreateUsingSystemProxyResolver(
         proxy_config_service,
         num_pac_threads,
         net_log);
   }
 
   return proxy_service;
 }