update_engine: fixed warnings from cpplint
Fixed all the cpplint warnings in update engine.
BUG=None
TEST=Unit tests still pass.
Change-Id: I285ae858eec8abe0b26ff203b99a42a200ceb71c
Reviewed-on: https://chromium-review.googlesource.com/204027
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/prefs.h b/prefs.h
index f05da0a..0ca221b 100644
--- a/prefs.h
+++ b/prefs.h
@@ -5,6 +5,8 @@
#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_PREFS_H_
#define CHROMEOS_PLATFORM_UPDATE_ENGINE_PREFS_H_
+#include <string>
+
#include <base/files/file_path.h>
#include "gtest/gtest_prod.h" // for FRIEND_TEST
#include "update_engine/prefs_interface.h"