Re-land: Toggle spoken feedback if two fingers are held down.

ash/ash_touch_exploration_manager_chromeos.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_TOUCH_EXPLORATION_MANAGER_CHROMEOS_H_
 #define ASH_TOUCH_EXPLORATION_MANAGER_CHROMEOS_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/common/system/accessibility_observer.h"
 #include "base/macros.h"
+#include "ui/chromeos/touch_accessibility_enabler.h"
 #include "ui/chromeos/touch_exploration_controller.h"
 #include "ui/display/display_observer.h"
 #include "ui/wm/public/activation_change_observer.h"
 
 namespace chromeos {
 class CrasAudioHandler;
 }
 
 namespace ash {
 class RootWindowController;
 
 // Responsible for initializing TouchExplorationController when spoken
 // feedback is on for ChromeOS only. This class implements
 // TouchExplorationControllerDelegate which allows touch gestures to manipulate
 // the system.
 class ASH_EXPORT AshTouchExplorationManager
     : public AccessibilityObserver,
       public ui::TouchExplorationControllerDelegate,
+      public ui::TouchAccessibilityEnablerDelegate,
       public display::DisplayObserver,
       public aura::client::ActivationChangeObserver {
  public:
   explicit AshTouchExplorationManager(
       RootWindowController* root_window_controller);
   ~AshTouchExplorationManager() override;
 
   // AccessibilityObserver overrides:
   void OnAccessibilityModeChanged(
       AccessibilityNotificationVisibility notify) override;
 
   // TouchExplorationControllerDelegate overrides:
   void SetOutputLevel(int volume) override;
   void SilenceSpokenFeedback() override;
   void PlayVolumeAdjustEarcon() override;
   void PlayPassthroughEarcon() override;
   void PlayExitScreenEarcon() override;
   void PlayEnterScreenEarcon() override;
   void HandleAccessibilityGesture(ui::AXGesture gesture) override;
 
   // display::DisplayObserver overrides:
   void OnDisplayMetricsChanged(const display::Display& display,
                                uint32_t changed_metrics) override;
 
+  // TouchAccessibilityEnablerDelegate overrides:
+  void PlaySpokenFeedbackToggleCountdown(int tick_count) override;
+  void ToggleSpokenFeedback() override;
+
   // aura::client::ActivationChangeObserver overrides:
   void OnWindowActivated(
       aura::client::ActivationChangeObserver::ActivationReason reason,
       aura::Window* gained_active,
       aura::Window* lost_active) override;
 
   // Update the touch exploration controller so that synthesized touch
   // events are anchored at this point.
   void SetTouchAccessibilityAnchorPoint(const gfx::Point& anchor_point);
 
  private:
   void UpdateTouchExplorationState();
   bool VolumeAdjustSoundEnabled();
 
   std::unique_ptr<ui::TouchExplorationController> touch_exploration_controller_;
+  std::unique_ptr<ui::TouchAccessibilityEnabler> touch_accessibility_enabler_;
   RootWindowController* root_window_controller_;
   chromeos::CrasAudioHandler* audio_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(AshTouchExplorationManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_TOUCH_EXPLORATION_MANAGER_CHROMEOS_H_