AU: Try delta updates first, then full updates

src/platform/update_engine/download_action.h

Index: src/platform/update_engine/download_action.h
diff --git a/src/platform/update_engine/download_action.h b/src/platform/update_engine/download_action.h
index e6939e125e231bc43b9e567753781080a352dc88..d5ec026962141613a40571577592282c2a0b0ec0 100644
--- a/src/platform/update_engine/download_action.h
+++ b/src/platform/update_engine/download_action.h
@@ -9,7 +9,6 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
-#include <map>
 #include <string>
 
 #include <curl/curl.h>
@@ -25,9 +24,6 @@
 // The Download Action downloads a requested url to a specified path on disk.
 // The url and output path are determined by the InstallPlan passed in.
 
-using std::map;
-using std::string;
-
 namespace chromeos_update_engine {
 
 class DownloadAction;