[Download Notification] Refine retry logic when interrupted or cancelled

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 "base/command_line.h"
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/grit/generated_resources.h"
 #include "content/public/common/content_switches.h"
@@ skipping 147 matching lines @@
       break;
     case DownloadCommands::CANCEL:
       id = IDS_DOWNLOAD_MENU_CANCEL;
       break;
     case DownloadCommands::LEARN_MORE_SCANNING:
       id = IDS_DOWNLOAD_MENU_LEARN_MORE_SCANNING;
       break;
     case DownloadCommands::LEARN_MORE_INTERRUPTED:
       id = IDS_DOWNLOAD_MENU_LEARN_MORE_INTERRUPTED;
       break;
-    case DownloadCommands::RETRY:
-      NOTREACHED();
-      return base::string16();
   }
   CHECK(id != -1);
   return l10n_util::GetStringUTF16(id);
 }
 
 void DownloadShelfContextMenu::DetachFromDownloadItem() {
   if (!download_item_)
     return;
 
   download_commands_.reset();
@@ skipping 137 matching lines @@
   if (malicious_download_menu_model_)
     return malicious_download_menu_model_.get();
 
   malicious_download_menu_model_.reset(new ui::SimpleMenuModel(this));
   malicious_download_menu_model_->AddItem(
       DownloadCommands::LEARN_MORE_SCANNING,
       GetLabelForCommandId(DownloadCommands::LEARN_MORE_SCANNING));
 
   return malicious_download_menu_model_.get();
 }