Make TabContents ctor private; poke hole for existing callers.

chrome/browser/chromeos/login/simple_web_view_dialog.cc

Index: chrome/browser/chromeos/login/simple_web_view_dialog.cc
diff --git a/chrome/browser/chromeos/login/simple_web_view_dialog.cc b/chrome/browser/chromeos/login/simple_web_view_dialog.cc
index fb1c3af9cb20413369175bec14e4d4ff2c5263a3..c9d9ca96321d1b2f18ee558fbf16a5c9dafaf80f 100644
--- a/chrome/browser/chromeos/login/simple_web_view_dialog.cc
+++ b/chrome/browser/chromeos/login/simple_web_view_dialog.cc
@@ -151,7 +151,7 @@ void SimpleWebViewDialog::StartLoad(const GURL& url) {
                           NULL,
                           MSG_ROUTING_NONE,
                           NULL);
-  tab_contents_.reset(new TabContents(web_contents));
+  tab_contents_.reset(TabContents::Factory::CreateTabContents(web_contents));
   web_view_->SetWebContents(web_contents);
   web_contents->SetDelegate(this);
   web_view_->LoadInitialURL(url);