Convert TrayAccessibility to wm common types

ash/keyboard/keyboard_ui.cc

 // Copyright 2016 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.
 
 #include "ash/keyboard/keyboard_ui.h"
 
 #include "ash/common/accessibility_delegate.h"
+#include "ash/common/system/accessibility_observer.h"
+#include "ash/common/system/tray/wm_system_tray_notifier.h"
+#include "ash/common/wm_shell.h"
 #include "ash/keyboard/keyboard_ui_observer.h"
-#include "ash/shell.h"
-#include "ash/system/tray/system_tray_notifier.h"
 #include "ash/system/tray_accessibility.h"
 #include "base/memory/ptr_util.h"
 #include "ui/keyboard/keyboard_controller.h"
 
 namespace ash {
 
 class KeyboardUIImpl : public KeyboardUI, public AccessibilityObserver {
  public:
   KeyboardUIImpl() {
-    // The Shell may not exist in some unit tests.
-    Shell::GetInstance()->system_tray_notifier()->AddAccessibilityObserver(
-        this);
+    WmShell::Get()->system_tray_notifier()->AddAccessibilityObserver(this);
   }
 
-  ~KeyboardUIImpl() override {}
+  ~KeyboardUIImpl() override {
+    if (WmShell::HasInstance() && WmShell::Get()->system_tray_notifier())
+      WmShell::Get()->system_tray_notifier()->RemoveAccessibilityObserver(this);
+  }
 
   // KeyboardUI:
   void Show() override {
     keyboard::KeyboardController::GetInstance()->ShowKeyboard(true);
   }
   void Hide() override {
     // Do nothing as this is called from ash::Shell, which also calls through
     // to the appropriate keyboard functions.
   }
   bool IsEnabled() override {
-    return Shell::GetInstance()
-        ->accessibility_delegate()
+    return WmShell::Get()
+        ->GetAccessibilityDelegate()
         ->IsVirtualKeyboardEnabled();
   }
 
   // AccessibilityObserver:
   void OnAccessibilityModeChanged(
       ui::AccessibilityNotificationVisibility notify) override {
     FOR_EACH_OBSERVER(KeyboardUIObserver, *observers(),
                       OnKeyboardEnabledStateChanged(IsEnabled()));
   }
 
@@ skipping 12 matching lines @@
   observers_.AddObserver(observer);
 }
 
 void KeyboardUI::RemoveObserver(KeyboardUIObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 KeyboardUI::KeyboardUI() {}
 
 }  // namespace ash