Implement chrome.experimental.downloads.onChanged

chrome/browser/extensions/extension_downloads_api_constants.cc

 // 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.
 
 #include "chrome/browser/extensions/extension_downloads_api_constants.h"
 
 namespace extension_downloads_api_constants {
 
 // Error messages
 const char kNotImplemented[] = "NotImplemented";
@@ skipping 40 matching lines @@
 }
 
 const char* StateString(DownloadItem::DownloadState state) {
   switch (state) {
     case DownloadItem::IN_PROGRESS: return kStateInProgress;
     case DownloadItem::COMPLETE: return kStateComplete;
     case DownloadItem::INTERRUPTED:  // fall through
     case DownloadItem::CANCELLED: return kStateInterrupted;
     case DownloadItem::REMOVING:  // fall through
     default:
-      NOTREACHED();
+      NOTREACHED() << state;
       return "";
   }
 }
 }  // namespace extension_downloads_api_constants