Move SessionStorageNamespace entirely into NavigationController and support StoragePartitions.

content/shell/shell.cc

Index: content/shell/shell.cc
diff --git a/content/shell/shell.cc b/content/shell/shell.cc
index a481a6840a36c36fa6e6ca9f4ce92ac3c4f4f075..2e40da075375bc16d38cc5e1830666bef5af55ca 100644
--- a/content/shell/shell.cc
+++ b/content/shell/shell.cc
@@ -110,8 +110,7 @@ Shell* Shell::CreateNewWindow(BrowserContext* browser_context,
       browser_context,
       site_instance,
       routing_id,
-      base_web_contents,
-      NULL);
+      base_web_contents);
   Shell* shell = CreateShell(web_contents);
   if (!url.is_empty())
     shell->LoadURL(url);