ash: Add a heads-up display to track touch-point states and positions.

ash/ash_switches.cc

Index: ash/ash_switches.cc
diff --git a/ash/ash_switches.cc b/ash/ash_switches.cc
index 4342a86d01a172c7772bd5b9b941d7caa7928d40..b8b63a2101a3a8a1e6383c73f350ea99081aa715 100644
--- a/ash/ash_switches.cc
+++ b/ash/ash_switches.cc
@@ -13,6 +13,9 @@ const char kAshEnableOak[] = "ash-enable-oak";
 // Use Ash notifications.
 const char kAshNotify[] = "ash-notify";
 
+// Enables the heads-up display for tracking touch points.
+const char kAshTouchHud[] = "ash-touch-hud";
+
 // Use Google-style dialog box frames.
 const char kAuraGoogleDialogFrames[] = "aura-google-dialog-frames";