arc: Logging ARC data removal reasons

chrome/browser/chromeos/arc/arc_optin_uma.h

Index: chrome/browser/chromeos/arc/arc_optin_uma.h
diff --git a/chrome/browser/chromeos/arc/arc_optin_uma.h b/chrome/browser/chromeos/arc/arc_optin_uma.h
index c6cd240b3587393f964846bf8a64a80c32d723ae..4e4f534ed176f708a65ab57527624407572d8949 100644
--- a/chrome/browser/chromeos/arc/arc_optin_uma.h
+++ b/chrome/browser/chromeos/arc/arc_optin_uma.h
@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_CHROMEOS_ARC_ARC_OPTIN_UMA_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_OPTIN_UMA_H_
 
+#include <ostream>
+
 namespace base {
 class TimeDelta;
 }
@@ -120,6 +122,9 @@ void UpdateProvisioningTiming(const base::TimeDelta& elapsed_time,
                               bool managed);
 void UpdateSilentAuthCodeUMA(OptInSilentAuthCode state);
 
+// Outputs the stringified |result| to |os|. This is only for logging purposes.
+std::ostream& operator<<(std::ostream& os, const ProvisioningResult& result);
+
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_OPTIN_UMA_H_