Fix Volume slider is captured in screenshot done in touchview mode

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 970ddab86dc8ce1bec159fa736c39dad267c7513..f932fb446ae25888896e2a8e2c7743d5d7a393d0 100644
--- a/ash/wm/power_button_controller.h
+++ b/ash/wm/power_button_controller.h
@@ -80,6 +80,8 @@ class ASH_EXPORT PowerButtonController
  private:
   friend class test::PowerButtonControllerTest;
 
+  void TakingScreenshot();

[Daniel Erat, 2016/07/28 04:45:00]

rename to TakeScreenshot and add a comment describing how this is used 

[Qiang(Joe) Xu, 2016/07/28 20:25:03]

done by deleting this method.

+
   // Are the power or lock buttons currently held?
   bool power_button_down_;
   bool lock_button_down_;
@@ -87,6 +89,9 @@ class ASH_EXPORT PowerButtonController
   // True when the volume down button is being held down.
   bool volume_down_pressed_;
 
+  // Volume to be restored after a maximize mode screenshot.
+  int saved_volume_percent_;

[Daniel Erat, 2016/07/28 04:45:00]

nit: rename this to something like volume_percent_before_screenshot_ so it's a
bit clearer when it was saved

[Qiang(Joe) Xu, 2016/07/28 20:25:02]

Done.

+
   // Has the screen brightness been reduced to 0%?
   bool brightness_is_zero_;