Show a notification when a braille display is connected.

ash/accessibility_delegate.h

 // Copyright 2013 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_ACCESSIBILITY_DELEGATE_H_
 #define ASH_ACCESSIBILITY_DELEGATE_H_
 
 #include "ash/ash_export.h"
 #include "ash/magnifier/magnifier_constants.h"
 #include "base/time/time.h"
 
 namespace ash {
 
 enum AccessibilityNotificationVisibility {
   A11Y_NOTIFICATION_NONE,
   A11Y_NOTIFICATION_SHOW,
 };
 
 enum AccessibilityAlert {
   A11Y_ALERT_NONE,
   A11Y_ALERT_WINDOW_NEEDED
 };
 
-// A deletate class to control accessibility features.
+// A delegate class to control and query accessibility features.
 class ASH_EXPORT AccessibilityDelegate {
  public:
   virtual ~AccessibilityDelegate() {}
 
   // Invoked to toggle spoken feedback for accessibility
   virtual void ToggleSpokenFeedback(
       AccessibilityNotificationVisibility notify) = 0;
 
   // Returns true if spoken feedback is enabled.
   virtual bool IsSpokenFeedbackEnabled() const = 0;
 
   // Invoked to toggle high contrast mode for accessibility.
   virtual void ToggleHighContrast() = 0;
 
   // Returns true if high contrast mode is enabled.
   virtual bool IsHighContrastEnabled() const = 0;
 
   // Invoked to enable the screen magnifier.
   virtual void SetMagnifierEnabled(bool enabled) = 0;
 
   // Invoked to change the type of the screen magnifier.
   virtual void SetMagnifierType(MagnifierType type) = 0;
 
-  // Returns true if the screen magnifier is enabled or not.
+  // Returns true if the screen magnifier is enabled.
   virtual bool IsMagnifierEnabled() const = 0;
 
   // Returns the current screen magnifier mode.
   virtual MagnifierType GetMagnifierType() const = 0;
 
   // Invoked to enable Large Cursor.
   virtual void SetLargeCursorEnabled(bool enabled) = 0;
 
-  // Returns ture if Large Cursor is enabled or not.
+  // Returns ture if Large Cursor is enabled.
   virtual bool IsLargeCursorEnabled() const = 0;
 
   // Invoked to enable autoclick.
   virtual void SetAutoclickEnabled(bool enabled) = 0;
 
   // Returns if autoclick is enabled or not.
   virtual bool IsAutoclickEnabled() const = 0;
 
   // Invoked to enable or disable the a11y on-screen keyboard.
   virtual void SetVirtualKeyboardEnabled(bool enabled) = 0;
 
   // Returns if the a11y virtual keyboard is enabled.
   virtual bool IsVirtualKeyboardEnabled() const = 0;
 
   // Returns true when the accessibility menu should be shown.
   virtual bool ShouldShowAccessibilityMenu() const = 0;
 
+  // Returns true if a braille display is connected to the system.
+  virtual bool IsBrailleDisplayConnected() = 0;

[oshima, 2014/03/26 19:42:54]

nit: can this be const?

+
   // Cancel all current and queued speech immediately.
   virtual void SilenceSpokenFeedback() const = 0;
 
   // Saves the zoom scale of the full screen magnifier.
   virtual void SaveScreenMagnifierScale(double scale) = 0;
 
   // Gets a saved value of the zoom scale of full screen magnifier. If a value
   // is not saved, return a negative value.
   virtual double GetSavedScreenMagnifierScale() = 0;
 
   // Triggers an accessibility alert to give the user feedback.
   virtual void TriggerAccessibilityAlert(AccessibilityAlert alert) = 0;
 
   // Gets the last accessibility alert that was triggered.
   virtual AccessibilityAlert GetLastAccessibilityAlert() = 0;
 
   // Initiates play of shutdown sound and returns it's duration.
   virtual base::TimeDelta PlayShutdownSound() const = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_ACCESSIBILITYDELEGATE_H_