Make WebContentsImpl::UpdateState navigation enties DCHECK conditional

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 3941 matching lines @@
   // when the user is scrolling and entering form data, as well as when we're
   // leaving a page, in which case our state may have already been moved to
   // the next page. The navigation controller will look up the appropriate
   // NavigationEntry and update it when it is notified via the delegate.
   RenderViewHostImpl* rvhi = static_cast<RenderViewHostImpl*>(rvh);
   NavigationEntryImpl* entry = controller_.GetEntryWithPageID(
       rvhi->GetSiteInstance(), page_id);
   if (!entry)
     return;
 
-  NavigationEntryImpl* new_entry = controller_.GetEntryWithUniqueID(
-      static_cast<RenderFrameHostImpl*>(rvhi->GetMainFrame())->nav_entry_id());
+  // Sanity check that ensures nav_entry_id and page_id point to the same
+  // navigation entry.
+  if (rvhi->GetMainFrame()) {
+    NavigationEntryImpl* new_entry = controller_.GetEntryWithUniqueID(
+        static_cast<RenderFrameHostImpl*>(rvhi->GetMainFrame())
+            ->nav_entry_id());
 
-  DCHECK_EQ(entry, new_entry);
+    DCHECK_EQ(entry, new_entry);
+  }
 
   if (page_state == entry->GetPageState())
     return;  // Nothing to update.
   entry->SetPageState(page_state);
   controller_.NotifyEntryChanged(entry);
 }
 
 void WebContentsImpl::UpdateTargetURL(RenderViewHost* render_view_host,
                                       const GURL& url) {
   if (fullscreen_widget_routing_id_ != MSG_ROUTING_NONE) {
@@ skipping 732 matching lines @@
     const WebContentsObserver::MediaPlayerId& id) {
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, MediaStartedPlaying(id));
 }
 
 void WebContentsImpl::MediaStoppedPlaying(
     const WebContentsObserver::MediaPlayerId& id) {
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, MediaStoppedPlaying(id));
 }
 
 }  // namespace content