Add the --disable-off-store-extension-install switch.

chrome/browser/download/download_shelf_context_menu.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 "chrome/browser/download/download_shelf_context_menu.h"
 
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/download/download_crx_util.h"
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/safe_browsing/download_protection_service.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
 #include "chrome/common/extensions/extension.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
@@ skipping 18 matching lines @@
   else if (download_item_->IsComplete())
     model = GetFinishedMenuModel();
   else
     model = GetInProgressMenuModel();
   return model;
 }
 
 bool DownloadShelfContextMenu::IsCommandIdEnabled(int command_id) const {
   switch (command_id) {
     case SHOW_IN_FOLDER:
-    case OPEN_WHEN_COMPLETE:
-      // Don't enable "Open when complete" if the download is no longer
-      // available or if it is temporary. We explicitly ignore "Open when
-      // complete" for temporary downloads.
       return download_item_->CanShowInFolder() &&
           !download_item_->IsTemporary();
+    case OPEN_WHEN_COMPLETE:
+      return download_item_->CanShowInFolder() &&
+          !download_item_->IsTemporary() &&
+          (!Extension::IsExtension(download_item_->GetTargetName()) ||
+           download_crx_util::ShouldOpenExtensionDownload(*download_item_));
     case ALWAYS_OPEN_TYPE:
       // For temporary downloads, the target filename might be a temporary
       // filename. Don't base an "Always open" decision based on it. Also
       // exclude extensions.
       return download_item_->CanOpenDownload() &&
           !Extension::IsExtension(download_item_->GetTargetName()) &&
           !download_item_->IsTemporary();
     case CANCEL:
       return download_item_->IsPartialDownload();
     case TOGGLE_PAUSE:
@@ skipping 162 matching lines @@
   malicious_download_menu_model_->AddItemWithStringId(
       DISCARD, IDS_DOWNLOAD_MENU_DISCARD);
   malicious_download_menu_model_->AddItemWithStringId(
       KEEP, IDS_DOWNLOAD_MENU_KEEP);
   malicious_download_menu_model_->AddSeparator();
   malicious_download_menu_model_->AddItemWithStringId(
       LEARN_MORE, IDS_DOWNLOAD_MENU_LEARN_MORE);
 
   return malicious_download_menu_model_.get();
 }