Disable support for swapped out RenderFrame(Host)

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 4755716effca5085531146e6c63cf52996454939..a093dff219dc24bb4d7158472428d49dbdf483b7 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -3959,10 +3959,13 @@ void WebContentsImpl::UpdateState(RenderViewHost* rvh,
   if (!entry)
     return;
 
-  NavigationEntryImpl* new_entry = controller_.GetEntryWithUniqueID(
-      static_cast<RenderFrameHostImpl*>(rvhi->GetMainFrame())->nav_entry_id());
+  if (rvhi->GetMainFrame()) {
+    NavigationEntryImpl* new_entry = controller_.GetEntryWithUniqueID(

[Charlie Reis, 2015/12/16 17:52:25]

Please add a comment that this is a sanity check to ensure nav_entry_id and
page_id point to the same entry.

+        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.