Move ProxyConfigService construction onto the IO thread.

content/shell/shell_url_request_context_getter.cc

Index: content/shell/shell_url_request_context_getter.cc
diff --git a/content/shell/shell_url_request_context_getter.cc b/content/shell/shell_url_request_context_getter.cc
index f612fa56a61f9e4d043da2a31e1daf151306c072..198937cd48a3d6dd7f4ace147d0fb87bd1bffbac 100644
--- a/content/shell/shell_url_request_context_getter.cc
+++ b/content/shell/shell_url_request_context_getter.cc
@@ -39,15 +39,6 @@ ShellURLRequestContextGetter::ShellURLRequestContextGetter(
       base_path_(base_path),
       io_loop_(io_loop),
       file_loop_(file_loop) {
-  // Must first be created on the UI thread.
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  // We must create the proxy config service on the UI loop on Linux because it
-  // must synchronously run on the glib message loop. This will be passed to
-  // the URLRequestContextStorage on the IO thread in GetURLRequestContext().
-  proxy_config_service_.reset(
-      net::ProxyService::CreateSystemProxyConfigService(
-          io_loop_->message_loop_proxy(), file_loop_));
 }
 
 ShellURLRequestContextGetter::~ShellURLRequestContextGetter() {
@@ -76,6 +67,10 @@ net::URLRequestContext* ShellURLRequestContextGetter::GetURLRequestContext() {
                                       net::HostResolver::kDefaultRetryAttempts,
                                       NULL));
     storage_->set_cert_verifier(net::CertVerifier::CreateDefault());
+    proxy_config_service_.reset(
+        net::ProxyService::CreateSystemProxyConfigService(
+            BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI),
+            file_loop_));
     // TODO(jam): use v8 if possible, look at chrome code.
     storage_->set_proxy_service(
         net::ProxyService::CreateUsingSystemProxyResolver(