AU: Try delta updates first, then full updates

src/platform/update_engine/action_unittest.cc

Index: src/platform/update_engine/action_unittest.cc
diff --git a/src/platform/update_engine/action_unittest.cc b/src/platform/update_engine/action_unittest.cc
index 371f84d6ac2e8df425adabf78b25420c6f82aded..8dd9edd52e3986b6af217b87ac795437c846a0a8 100644
--- a/src/platform/update_engine/action_unittest.cc
+++ b/src/platform/update_engine/action_unittest.cc
@@ -2,10 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <string>
 #include <gtest/gtest.h>
 #include "update_engine/action.h"
 #include "update_engine/action_processor.h"
 
+using std::string;
+
 namespace chromeos_update_engine {
 
 using chromeos_update_engine::ActionPipe;