AU: Try delta updates first, then full updates

src/platform/update_engine/action_pipe_unittest.cc

Index: src/platform/update_engine/action_pipe_unittest.cc
diff --git a/src/platform/update_engine/action_pipe_unittest.cc b/src/platform/update_engine/action_pipe_unittest.cc
index 28cf24841179fc00613d460599d418ac07c175a6..b0a96b78e019d22542aaab83f80ab3ed846809b0 100644
--- a/src/platform/update_engine/action_pipe_unittest.cc
+++ b/src/platform/update_engine/action_pipe_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_pipe.h"
 
+using std::string;
+
 namespace chromeos_update_engine {
 
 using chromeos_update_engine::ActionPipe;