Fix crash in update_client::BackgroundDownloader::EndDownload.

components/update_client/background_downloader_win.h

Index: components/update_client/background_downloader_win.h
diff --git a/components/update_client/background_downloader_win.h b/components/update_client/background_downloader_win.h
index 563a2601e7d92edadfd9067579d34b4cad1ca1d1..f0d5ecd62526c4c2993c6092dc78f98130693008 100644
--- a/components/update_client/background_downloader_win.h
+++ b/components/update_client/background_downloader_win.h
@@ -85,6 +85,10 @@ class BackgroundDownloader : public CrxDownloader {
   void StartTimer();
   void OnTimer();
 
+  // Returns true if the timer is running or false if the timer is not
+  // created or not running at all.
+  bool TimerIsRunning() const;
+
   HRESULT QueueBitsJob(const GURL& url, IBackgroundCopyJob** job);
   HRESULT CreateOrOpenJob(const GURL& url, IBackgroundCopyJob** job);
   HRESULT InitializeNewJob(