[Chrome OS MD] Implement accessibility detailed view for the MD Ash system menu

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 b9d3a32af79e21e088847e920ffa694aa524518a..a38db67ad1ab87df0d41b222f96b1e5d790de0ca 100644
--- a/ash/common/system/tray/tray_constants.h
+++ b/ash/common/system/tray/tray_constants.h
@@ -97,6 +97,12 @@ extern const SkColor kTrayIconColor;
 extern const int kMenuIconSize;
 extern const SkColor kMenuIconColor;
 
+// The margin between the edge of the menu and the edge of the button.
+extern const int kMenuIconMargin;
+
+// The size of buttons in the system menu.
+extern const int kMenuButtonSize;

[tdanderson, 2016/09/21 17:59:32]

kMenuButtonSize was added by another CL, make sure you pull, rebase, and fix
merge conflicts before putting this in the CQ.

[yiyix, 2016/09/21 19:02:26]

Sure, i will rebase the code before send to other people for review. Thank you
for the call out.

+
 enum TrayConstant {
   // A legacy height value used in non-MD calculations for applying additional
   // borders on tray items.