Speculative fix for crash. Crashes seem to indicate

chrome/browser/extensions/extension_webnavigation_api.h

Index: chrome/browser/extensions/extension_webnavigation_api.h
diff --git a/chrome/browser/extensions/extension_webnavigation_api.h b/chrome/browser/extensions/extension_webnavigation_api.h
index 1f7e7a1036093c8cc41504f007a96e1b3f9b3877..7b8355e980037fdbd0df07e7dd5d8e5d86b5fd88 100644
--- a/chrome/browser/extensions/extension_webnavigation_api.h
+++ b/chrome/browser/extensions/extension_webnavigation_api.h
@@ -198,6 +198,10 @@ class ExtensionWebNavigationEventRouter : public NotificationObserver {
   // of such an event and creates a JSON formated extension event from it.
   void TabAdded(TabContents* tab_contents);
 
+  // Handler for NOTIFICATION_TAB_CONTENTS_DESTROYED. If |tab_contents| is
+  // in |pending_tab_contents_|, it is removed.
+  void TabDestroyed(TabContents* tab_contents);
+
   // Mapping pointers to TabContents objects to information about how they got
   // created.
   std::map<TabContents*, PendingTabContents> pending_tab_contents_;