Don't split off NTP subframes with TDI.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 6cbb744a4ea1f4b287ca77411cc7e4cca2ccb8cd..6cc53b8d76292097e08add81fc8b1f0dce528ad5 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -79,6 +79,13 @@ bool ContentBrowserClient::ShouldAllowOpenURL(SiteInstance* site_instance,
   return true;
 }
 
+bool ContentBrowserClient::
+    ShouldFrameShareParentSiteInstanceDespiteTopDocumentIsolation(
+        const GURL& url,
+        SiteInstance* parent_site_instance) {
+  return false;
+}
+
 bool ContentBrowserClient::IsSuitableHost(RenderProcessHost* process_host,
                                           const GURL& site_url) {
   return true;