Added quick lock mechanism while in Touchview

ash/wm/power_button_controller.h

Index: ash/wm/power_button_controller.h
diff --git a/ash/wm/power_button_controller.h b/ash/wm/power_button_controller.h
index f1780146c773ccb41e003f4061c7049d2d3baf58..ecab2a30bbab5fe6162ea86bcdfb1b5802346dd0 100644
--- a/ash/wm/power_button_controller.h
+++ b/ash/wm/power_button_controller.h
@@ -5,9 +5,12 @@
 #ifndef ASH_WM_POWER_BUTTON_CONTROLLER_H_
 #define ASH_WM_POWER_BUTTON_CONTROLLER_H_
 
+#include "ash/accelerators/accelerator_controller.h"
+#include "ash/accelerators/accelerator_table.h"
 #include "ash/ash_export.h"
 #include "ash/wm/session_state_animator.h"
 #include "base/basictypes.h"
+#include "ui/base/accelerators/accelerator.h"
 
 #if defined(OS_CHROMEOS)
 #include "ui/display/chromeos/display_configurator.h"
@@ -30,13 +33,14 @@ class PowerButtonControllerTest;
 
 class LockStateController;
 
-// Displays onscreen animations and locks or suspends the system in response to
-// the power button being pressed or released.
+// Handles power & lock button events which may result in the locking or
+// shutting down of the system as well as taking screen shots.
 class ASH_EXPORT PowerButtonController
+    : ui::EventHandler
 // TODO(derat): Remove these ifdefs after DisplayConfigurator becomes
 // cross-platform.
 #if defined(OS_CHROMEOS)
-    : public ui::DisplayConfigurator::Observer
+    , public ui::DisplayConfigurator::Observer
 #endif
       {
  public:
@@ -54,6 +58,9 @@ class ASH_EXPORT PowerButtonController
   void OnPowerButtonEvent(bool down, const base::TimeTicks& timestamp);
   void OnLockButtonEvent(bool down, const base::TimeTicks& timestamp);
 
+  // ui::EventHandler:
+  virtual void OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
+
 #if defined(OS_CHROMEOS)
   // Overriden from ui::DisplayConfigurator::Observer:
   virtual void OnDisplayModeChanged(
@@ -67,6 +74,9 @@ class ASH_EXPORT PowerButtonController
   bool power_button_down_;
   bool lock_button_down_;
 
+  // True when the volume down button is being held down.
+  bool volume_down_pressed_;
+
   // Has the screen brightness been reduced to 0%?
   bool brightness_is_zero_;
 
@@ -79,7 +89,7 @@ class ASH_EXPORT PowerButtonController
   // that misreports power button releases?
   bool has_legacy_power_button_;
 
-  LockStateController* controller_; // Not owned.
+  LockStateController* controller_;  // Not owned.
 
   DISALLOW_COPY_AND_ASSIGN(PowerButtonController);
 };