Remember User locked rotation

ash/system/chromeos/rotation/tray_rotation_lock.cc

Index: ash/system/chromeos/rotation/tray_rotation_lock.cc
diff --git a/ash/system/chromeos/rotation/tray_rotation_lock.cc b/ash/system/chromeos/rotation/tray_rotation_lock.cc
index 9b1ba257c53890b5c555baadcab43412c21fce5b..b930895fdf6a7de1da52a8b04a4da3986d1f7911 100644
--- a/ash/system/chromeos/rotation/tray_rotation_lock.cc
+++ b/ash/system/chromeos/rotation/tray_rotation_lock.cc
@@ -164,6 +164,7 @@ TrayRotationLock::TrayRotationLock(SystemTray* system_tray)
 }
 
 TrayRotationLock::~TrayRotationLock() {
+  StopObservingRotation();

[jonross, 2017/03/24 16:46:49]

Are we sending state change notifications during shutdown? That's slightly
concerning.

[oshima, 2017/03/24 17:19:35]

This was for the test which wasn't following the normal destroction flow. I
changed the test instead.

[jonross, 2017/03/24 17:32:21]

Acknowledged.

   Shell::GetInstance()->RemoveShellObserver(this);
 }