Take a screenshot in maximize mode when volume down and power are pressed.

ash/wm/maximize_mode/maximize_mode_controller.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_CONTROLLER_H_
 #define ASH_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_CONTROLLER_H_
 
 #include "ash/accelerometer/accelerometer_observer.h"
 #include "ash/ash_export.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 
+namespace ui {
+class EventHandler;
+}
+
 namespace ash {
 
 class MaximizeModeEventBlocker;
 
 // MaximizeModeController listens to accelerometer events and automatically
 // enters and exits maximize mode when the lid is opened beyond the triggering
 // angle and rotates the display to match the device when in maximize mode.
 class ASH_EXPORT MaximizeModeController : public AccelerometerObserver {
  public:
   MaximizeModeController();
@@ skipping 23 matching lines @@
  private:
   // Detect hinge rotation from |base| and |lid| accelerometers and
   // automatically start / stop maximize mode.
   void HandleHingeRotation(const gfx::Vector3dF& base,
                            const gfx::Vector3dF& lid);
 
   // Detect screen rotation from |lid| accelerometer and automatically rotate
   // screen.
   void HandleScreenRotation(const gfx::Vector3dF& lid);
 
-  // An event handler which traps mouse and keyboard events while maximize
-  // mode is engaged.
+  // An event targeter controller which traps mouse and keyboard events while
+  // maximize mode is engaged.
   scoped_ptr<MaximizeModeEventBlocker> event_blocker_;
 
+  // An event handler used to detect screenshot actions while in maximize mode.
+  scoped_ptr<ui::EventHandler> event_handler_;
+
   // When true calls to OnAccelerometerUpdated will not rotate the display.
   bool rotation_locked_;
 
   // Whether we have ever seen accelerometer data.
   bool have_seen_accelerometer_data_;
 
   DISALLOW_COPY_AND_ASSIGN(MaximizeModeController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_CONTROLLER_H_