Introduce NetworkDelegate's implementation in extensions.

content/shell/browser/shell_url_request_context_getter.cc

Index: content/shell/browser/shell_url_request_context_getter.cc
diff --git a/content/shell/browser/shell_url_request_context_getter.cc b/content/shell/browser/shell_url_request_context_getter.cc
index c606d13cba040da14893d3af6cbb154097a0c33b..cd65b7738e4bfb6315e908f82f3ad61c4a5f96c9 100644
--- a/content/shell/browser/shell_url_request_context_getter.cc
+++ b/content/shell/browser/shell_url_request_context_getter.cc
@@ -91,6 +91,15 @@ ShellURLRequestContextGetter::ShellURLRequestContextGetter(
 ShellURLRequestContextGetter::~ShellURLRequestContextGetter() {
 }
 
+void ShellURLRequestContextGetter::set_network_delegate(
+    net::NetworkDelegate* network_delegate) {
+  network_delegate_.reset(network_delegate);
+}
+
+net::NetworkDelegate* ShellURLRequestContextGetter::CreateNetworkDelegate() {
+  return new ShellNetworkDelegate();
+}
+
 net::URLRequestContext* ShellURLRequestContextGetter::GetURLRequestContext() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
@@ -99,7 +108,8 @@ net::URLRequestContext* ShellURLRequestContextGetter::GetURLRequestContext() {
 
     url_request_context_.reset(new net::URLRequestContext());
     url_request_context_->set_net_log(net_log_);
-    network_delegate_.reset(new ShellNetworkDelegate);
+    if (!network_delegate_)
+      network_delegate_.reset(CreateNetworkDelegate());
     if (command_line.HasSwitch(switches::kDumpRenderTree))
       ShellNetworkDelegate::SetAcceptAllCookies(false);
     url_request_context_->set_network_delegate(network_delegate_.get());