Test file errors in downloads.

content/browser/download/download_file_manager.h

Index: content/browser/download/download_file_manager.h
diff --git a/content/browser/download/download_file_manager.h b/content/browser/download/download_file_manager.h
index b5f1654c4a74bf5323f64988d9fc932bb992fe76..779dafa79c6368ce49b0eec33ce9e19eb2cc2f33 100644
--- a/content/browser/download/download_file_manager.h
+++ b/content/browser/download/download_file_manager.h
@@ -144,6 +144,14 @@ class CONTENT_EXPORT DownloadFileManager
     return downloads_.size();
   }
 
+  void SetFileFactoryForTesting(scoped_ptr<DownloadFileFactory> file_factory) {
+    download_file_factory_.swap(file_factory);
+  }
+
+  DownloadFileFactory* GetFileFactoryForTesting() const {
+    return download_file_factory_.get();  // Explicitly NOT a scoped_ptr.
+  }
+
  private:
   friend class base::RefCountedThreadSafe<DownloadFileManager>;
   friend class DownloadFileManagerTest;