Fix instances of passing raw pointers to RefCounted objects in tasks.

chrome/browser/download/download_file_manager.cc

Index: chrome/browser/download/download_file_manager.cc
diff --git a/chrome/browser/download/download_file_manager.cc b/chrome/browser/download/download_file_manager.cc
index fc94314139d4c9eeec00764dc0e32fd13bb8a4c2..10fe2fe93f0830e155f93d90b60895426bebf337 100644
--- a/chrome/browser/download/download_file_manager.cc
+++ b/chrome/browser/download/download_file_manager.cc
@@ -174,9 +174,13 @@ void DownloadFileManager::StartDownload(DownloadCreateInfo* info) {
     return;
   }
 
-  ChromeThread::PostTask(ChromeThread::FILE, FROM_HERE,
-      NewRunnableMethod(this, &DownloadFileManager::CreateDownloadFile,
-                        info, manager));
+  ChromeThread::PostTask(
+      ChromeThread::FILE,
+      FROM_HERE,
+      NewRunnableMethod(this,
+                        &DownloadFileManager::CreateDownloadFile,
+                        info,
+                        make_scoped_refptr(manager)));
 }
 
 // We don't forward an update to the UI thread here, since we want to throttle