[ash-md] Added a delay between system menu default/detailed view transitions.

ash/common/system/tray/tray_constants.h

Index: ash/common/system/tray/tray_constants.h
diff --git a/ash/common/system/tray/tray_constants.h b/ash/common/system/tray/tray_constants.h
index 6b072a580477cc59cfd2b8dd4abaabd91bf06ecf..7a7c02d31d96e989f0a3289079aa2a359db1b138 100644
--- a/ash/common/system/tray/tray_constants.h
+++ b/ash/common/system/tray/tray_constants.h
@@ -171,6 +171,12 @@ enum TrayConstant {
   // The minimum default width for the right container of the system menu rows.
   TRAY_POPUP_ITEM_MIN_END_WIDTH,
 
+  // Duration to delay transitions to the default view.
+  TRAY_POPUP_TRANSITION_TO_DEFAULT_DELAY,
+
+  // Duration to delay transitions to the detailed view.
+  TRAY_POPUP_TRANSITION_TO_DETAILED_DELAY,
+
   // The width and height of the virtual keyboard button in the status tray
   // area. For non-MD, adjustments are made to the button dimensions based on
   // the shelf orientation, so this constant does not specify the true
@@ -184,7 +190,7 @@ enum TrayConstant {
   TRAY_IMAGE_ITEM_PADDING,
 };
 
-int GetTrayConstant(TrayConstant constant);
+ASH_EXPORT int GetTrayConstant(TrayConstant constant);
 
 namespace test {
 const int kSettingsTrayItemViewId = 10000;