Switch CaptivePortalTabHelper to use WebContentsUserData.

chrome/browser/captive_portal/captive_portal_browsertest.cc

Index: chrome/browser/captive_portal/captive_portal_browsertest.cc
diff --git a/chrome/browser/captive_portal/captive_portal_browsertest.cc b/chrome/browser/captive_portal/captive_portal_browsertest.cc
index 44848d9d7838f6feb9bf8f646373354cb66769a4..f002f6c7c7a49d7530dd63113682b661ed18b64b 100644
--- a/chrome/browser/captive_portal/captive_portal_browsertest.cc
+++ b/chrome/browser/captive_portal/captive_portal_browsertest.cc
@@ -485,7 +485,8 @@ int NumLoadingTabs() {
 }
 
 bool IsLoginTab(TabContents* tab_contents) {
-  return tab_contents->captive_portal_tab_helper()->IsLoginTab();
+  return CaptivePortalTabHelper::FromWebContents(
+      tab_contents->web_contents())->IsLoginTab();
 }
 
 // Tracks how many times each tab has been navigated since the Observer was
@@ -1539,7 +1540,8 @@ void CaptivePortalBrowserTest::SetSlowSSLLoadTime(
 
 CaptivePortalTabReloader* CaptivePortalBrowserTest::GetTabReloader(
     TabContents* tab_contents) const {
-  return tab_contents->captive_portal_tab_helper()->GetTabReloaderForTest();
+  return CaptivePortalTabHelper::FromWebContents(
+      tab_contents->web_contents())->GetTabReloaderForTest();
 }
 
 // Make sure there's no test for a captive portal on HTTP timeouts.  This will