Add "system" URLRequestContext (not ready for use!)

chrome/browser/io_thread.h

Index: chrome/browser/io_thread.h
diff --git a/chrome/browser/io_thread.h b/chrome/browser/io_thread.h
index 5730bb992851825f45733a3a041ba6567b3dc3a0..b6f09a7500ea12f9274af429aff3bc7a21abc3d4 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -58,6 +58,12 @@ class IOThread : public BrowserProcessSubThread {
     scoped_ptr<net::URLSecurityManager> url_security_manager;
     ChromeNetworkDelegate network_delegate;
     scoped_refptr<net::URLRequestContext> proxy_script_fetcher_context;
+    scoped_ptr<net::HttpTransactionFactory> system_http_transaction_factory;
+    scoped_refptr<net::ProxyService> system_proxy_service;
+    // NOTE(willchan): This request context is unusable until a system
+    // SSLConfigService and ProxyService are provided that don't rely on
+    // Profiles. Do NOT use this yet.
+    scoped_refptr<net::URLRequestContext> system_request_context;
   };
 
   // |net_log| must either outlive the IOThread or be NULL.