Cleanup ExtensionDownloadsEventRouter on download manager shutdown.

BUG=Debug browser_tests occasionally crash with failed DCHECK in ExtensionDownloadsEventRouter.


Review URL: https://chromiumcodereview.appspot.com/10829058

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148807 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/download/chrome_download_manager_delegate.cc

@@ -144,6 +144,9 @@ void ChromeDownloadManagerDelegate::SetDownloadManager(DownloadManager* dm) {
 void ChromeDownloadManagerDelegate::Shutdown() {
   download_history_.reset();
   download_prefs_.reset();
+#if !defined(OS_ANDROID)
+  extension_event_router_.reset();
+#endif
 }
 
 DownloadId ChromeDownloadManagerDelegate::GetNextId() {