content: Cleanup class/struct forward declarations

content/browser/download/download_file_factory.h

Index: content/browser/download/download_file_factory.h
diff --git a/content/browser/download/download_file_factory.h b/content/browser/download/download_file_factory.h
index afb921d7025df02b1a163d5c90f5fb9ec48b9ccd..f940377d78eda7f83fde97f53fd8c461af4b51e1 100644
--- a/content/browser/download/download_file_factory.h
+++ b/content/browser/download/download_file_factory.h
@@ -14,10 +14,6 @@
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
-namespace crypto {
-class SecureHash;
-}
-
 namespace net {
 class NetLogWithSource;
 }
@@ -27,7 +23,6 @@ namespace content {
 class ByteStreamReader;
 class DownloadDestinationObserver;
 class DownloadFile;
-class DownloadManager;
 struct DownloadSaveInfo;
 
 class CONTENT_EXPORT DownloadFileFactory {