Files.app: Add UMA for HardUnplugged events.

chrome/browser/chromeos/extensions/file_manager/device_event_router.h

Index: chrome/browser/chromeos/extensions/file_manager/device_event_router.h
diff --git a/chrome/browser/chromeos/extensions/file_manager/device_event_router.h b/chrome/browser/chromeos/extensions/file_manager/device_event_router.h
index a43ced26460e24547152dd703e67fb9bec387f95..c9b0591f5d61fbba8517315ee2399790aabe8d7b 100644
--- a/chrome/browser/chromeos/extensions/file_manager/device_event_router.h
+++ b/chrome/browser/chromeos/extensions/file_manager/device_event_router.h
@@ -98,6 +98,11 @@ class DeviceEventRouter : public VolumeManagerObserver,
   // Thread checker.
   base::ThreadChecker thread_checker_;
 
+  // Last event time for UMA.
+  // TODO(hirono): Remove the temporarily UMA.  crbug.com/433734
+  base::Time last_hard_unplugged_;
+  base::Time last_suspend_done_;
+
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate the weak pointers before any other members are destroyed.
   base::WeakPtrFactory<DeviceEventRouter> weak_factory_;