Uprev libchrome to r576279 (1/multiple)

* StatisticsRecorder no longer need call to Initialize()
* tracked_objects::Location -> base::Location
* base::*ToString replaced with base::NumberToString

Test: compilation
Change-Id: I5f912bd15f7cb26df3edc1ad7f4479122ffb6d7a
Merged-In: I5f912bd15f7cb26df3edc1ad7f4479122ffb6d7a
(cherry picked from commit b09c78648893f5a8225fb1c5f9ac49946682fe31)
diff --git a/update_boot_flags_action.h b/update_boot_flags_action.h
index 0d1125e..afa2c3f 100644
--- a/update_boot_flags_action.h
+++ b/update_boot_flags_action.h
@@ -19,6 +19,8 @@
 #include "update_engine/common/action.h"
 #include "update_engine/common/boot_control_interface.h"
 
+#include <gtest/gtest_prod.h>
+
 namespace chromeos_update_engine {
 
 class UpdateBootFlagsAction : public AbstractAction {