We have a problem in the process on destroying WebContentsImpl because

content/public/browser/web_contents_observer.cc

Index: content/public/browser/web_contents_observer.cc
diff --git a/content/public/browser/web_contents_observer.cc b/content/public/browser/web_contents_observer.cc
index fc0fcf253ac64657075472ac2775f34f442d9431..772a9ed3d6221da428bf0b0c413557b1523a87b6 100644
--- a/content/public/browser/web_contents_observer.cc
+++ b/content/public/browser/web_contents_observer.cc
@@ -61,12 +61,4 @@ int WebContentsObserver::routing_id() const {
   return web_contents_->GetRoutingID();
 }
 
-void WebContentsObserver::WebContentsImplDestroyed() {
-  // Do cleanup so that 'this' can safely be deleted from WebContentsDestroyed.
-  web_contents_->RemoveObserver(this);
-  WebContentsImpl* contents = web_contents_;
-  web_contents_ = NULL;
-  WebContentsDestroyed(contents);
-}
-
 }  // namespace content