Refactors keyboard related code so mash can use a keyboard

ash/keyboard/keyboard_ui.cc

Index: ash/keyboard/keyboard_ui.cc
diff --git a/ash/keyboard/keyboard_ui.cc b/ash/keyboard/keyboard_ui.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f760575f2bf7efe78ef9593e57344ea0e391d7ae
--- /dev/null
+++ b/ash/keyboard/keyboard_ui.cc
@@ -0,0 +1,68 @@
+// 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/accessibility_delegate.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 "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);
+  }
+
+  ~KeyboardUIImpl() override {}
+
+  // 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()
+        ->IsVirtualKeyboardEnabled();
+  }
+
+  // AccessibilityObserver:
+  void OnAccessibilityModeChanged(
+      ui::AccessibilityNotificationVisibility notify) override {
+    FOR_EACH_OBSERVER(KeyboardUIObserver, *observers(),
+                      OnKeyboardEnabledStateChanged(IsEnabled()));
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(KeyboardUIImpl);
+};
+
+KeyboardUI::~KeyboardUI() {}
+
+// static
+scoped_ptr<KeyboardUI> KeyboardUI::Create() {
+  return make_scoped_ptr(new KeyboardUIImpl);
+}
+
+void KeyboardUI::AddObserver(KeyboardUIObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void KeyboardUI::RemoveObserver(KeyboardUIObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+KeyboardUI::KeyboardUI() {}
+
+}  // namespace ash