Add a null check for last committed entry in ClassifyNavigation.

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 124346013c998a5b9e8c63f03feede3a243008a8..d998d43afd76f05dc52b2f5d110bc006b7e5916c 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -1011,7 +1011,8 @@ NavigationType NavigationControllerImpl::ClassifyNavigation(
     // make sure Blink didn't treat a new cross-process navigation as inert, and
     // thus set params.did_create_new_entry to false. In that case, we must
     // treat it as NEW since the SiteInstance doesn't match the entry.
-    if (GetLastCommittedEntry()->site_instance() != rfh->GetSiteInstance())
+    if (GetLastCommittedEntry() &&
+        GetLastCommittedEntry()->site_instance() != rfh->GetSiteInstance())
       return NAVIGATION_TYPE_NEW_PAGE;
 
     // Otherwise, this happens when you press enter in the URL bar to reload. We