MacViews: Refactor aura dependency from ExtensionPopup

chrome/browser/ui/views/extensions/extension_popup_aura.h

+// Copyright 2015 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 CHROME_BROWSER_UI_VIEWS_EXTENSIONS_EXTENSION_POPUP_AURA_H_
+#define CHROME_BROWSER_UI_VIEWS_EXTENSIONS_EXTENSION_POPUP_AURA_H_
+
+#include "chrome/browser/ui/views/extensions/extension_popup.h"
+#include "ui/wm/public/activation_change_observer.h"
+
+class ExtensionPopupAura : public ExtensionPopup,
+                           public aura::client::ActivationChangeObserver {
+ public:
+  ExtensionPopupAura(extensions::ExtensionViewHost* host,
+                     views::View* anchor_view,
+                     views::BubbleBorder::Arrow arrow,
+                     ShowAction show_action);
+  ~ExtensionPopupAura() override;
+
+  // views::WidgetObserver overrides.
+  void OnWidgetDestroying(views::Widget* widget) override;
+
+  // aura::client::ActivationChangeObserver overrides.
+  void OnWindowActivated(aura::Window* gained_active,
+                         aura::Window* lost_active) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ExtensionPopupAura);
+};
+
+#endif  // CHROME_BROWSER_UI_VIEWS_EXTENSIONS_EXTENSION_POPUP_AURA_H_