Added quick lock mechanism while in Touchview

ash/ash_switches.cc

Index: ash/ash_switches.cc
diff --git a/ash/ash_switches.cc b/ash/ash_switches.cc
index 87ffcc496cbd9c9366a94e606e105ff154e3dfd5..1240839ba855551c80f697eec7b543627ed40928 100644
--- a/ash/ash_switches.cc
+++ b/ash/ash_switches.cc
@@ -58,6 +58,10 @@ const char kAshEnableMagnifierKeyScroller[] =
 const char kAshDisableTextFilteringInOverviewMode[] =
     "ash-disable-text-filtering-in-overview-mode";
 
+// Enables quick, non-cancellable locking of the screen when in maximize mode.
+const char kAshEnablePowerButtonQuickLock[] =
+    "ash-enable-power-button-quick-lock";
+
 // Enables software based mirroring.
 const char kAshEnableSoftwareMirroring[] = "ash-enable-software-mirroring";