Move ProxyConfigService construction onto the IO thread.

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 6e0699cbe5a9be9bd3892ce1eb86aad9e55a1717..d8b8fbea7307a784d78d4c75f31460302af40709 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -19,6 +19,7 @@
 #include "net/base/network_change_notifier.h"
 
 class ChromeNetLog;
+class ChromeProxyConfigService;
 class PrefProxyConfigTrackerImpl;
 class PrefService;
 class SystemURLRequestContextGetter;
@@ -43,7 +44,6 @@ class HttpServerProperties;
 class HttpTransactionFactory;
 class NetworkDelegate;
 class ServerBoundCertService;
-class ProxyConfigService;
 class ProxyService;
 class SdchManager;
 class SSLConfigService;
@@ -144,6 +144,11 @@ class IOThread : public content::BrowserThreadDelegate {
   // called on the IO thread.
   void ClearHostCache();
 
+  // Called on the UI thread to indicate now is the time for shutdown work that
+  // must occur on the UI thread.  Its also one of the last safe times to post
+  // shutdown tasks to other browser threads.
+  void StartTearDown();
+
  private:
   // BrowserThreadDelegate implementation, runs on the IO thread.
   // This handles initialization and destruction of state that must
@@ -212,12 +217,12 @@ class IOThread : public content::BrowserThreadDelegate {
   // platform and it gets SSL preferences from local_state object.
   scoped_ptr<SSLConfigServiceManager> ssl_config_service_manager_;
 
-  // These member variables are initialized by a task posted to the IO thread,
-  // which gets posted by calling certain member functions of IOThread.
-  scoped_ptr<net::ProxyConfigService> system_proxy_config_service_;
+  scoped_ptr<ChromeProxyConfigService> system_proxy_config_service_;
 
   scoped_ptr<PrefProxyConfigTrackerImpl> pref_proxy_config_tracker_;
 
+  // This member variable is initialized by a task posted to the IO thread,
+  // which gets posted by calling certain member functions of IOThread.
   scoped_refptr<net::URLRequestContextGetter>
       system_url_request_context_getter_;