Don't close crashed tabs from extensions with background pages.

chrome/common/extensions/extension_constants.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_
 #pragma once
 
 #include <string>
 
@@ skipping 433 matching lines @@
     INSTALL_CAUSE_UPDATE,
     INSTALL_CAUSE_EXTERNAL_FILE,
     INSTALL_CAUSE_AUTOMATION,
     NUM_INSTALL_CAUSES
   };
 
   enum UnloadedExtensionReason {
     UNLOAD_REASON_DISABLE,    // Extension is being disabled.
     UNLOAD_REASON_UPDATE,     // Extension is being updated to a newer version.
     UNLOAD_REASON_UNINSTALL,  // Extension is being uninstalled.
+    UNLOAD_REASON_TERMINATE,  // Extension has terminated.
   };
 
   // User actions on the sync promo (aka "Sign in to Chrome").
   enum SyncPromoBuckets {
     SYNC_PROMO_VIEWED,
     SYNC_PROMO_LEARN_MORE_CLICKED,
     SYNC_PROMO_ACCOUNT_HELP_CLICKED,
     SYNC_PROMO_CREATE_ACCOUNT_CLICKED,
     SYNC_PROMO_SKIP_CLICKED,
     SYNC_PROMO_SIGN_IN_ATTEMPTED,
     SYNC_PROMO_SIGNED_IN_SUCCESSFULLY,
     SYNC_PROMO_ADVANCED_CLICKED,
     SYNC_PROMO_ENCRYPTION_HELP_CLICKED,
     SYNC_PROMO_CANCELLED_AFTER_SIGN_IN,
     SYNC_PROMO_CONFIRMED_AFTER_SIGN_IN,
     SYNC_PROMO_CLOSED_TAB,
     SYNC_PROMO_CLOSED_WINDOW,
     SYNC_PROMO_BUCKET_BOUNDARY,
     SYNC_PROMO_FIRST_VALID_JS_ACTION = SYNC_PROMO_LEARN_MORE_CLICKED,
     SYNC_PROMO_LAST_VALID_JS_ACTION = SYNC_PROMO_CONFIRMED_AFTER_SIGN_IN,
   };
 } // extension_misc
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_