Move SessionStorageNamespace entirely into NavigationController and support StoragePartitions.

chrome/browser/ui/browser_navigator.cc

Index: chrome/browser/ui/browser_navigator.cc
diff --git a/chrome/browser/ui/browser_navigator.cc b/chrome/browser/ui/browser_navigator.cc
index dc1134cb5b657ea341b540aec1d29382bab8e844..f24c2159efaa50127eca680f83a62e8144965ec7 100644
--- a/chrome/browser/ui/browser_navigator.cc
+++ b/chrome/browser/ui/browser_navigator.cc
@@ -472,8 +472,7 @@ void Navigate(NavigateParams* params) {
               tab_util::GetSiteInstanceForNewTab(
                   params->browser->profile(), url),
               MSG_ROUTING_NONE,
-              source_contents,
-              NULL);
+              source_contents);
       // This function takes ownership of |params->target_contents| until it
       // is added to a TabStripModel.
       target_contents_owner.TakeOwnership();