Fix autofill popup controller key press callback registration

components/autofill/content/browser/key_press_handler_manager.h

+// Copyright 2017 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 COMPONENTS_AUTOFILL_CONTENT_BROWSER_KEY_PRESS_HANDLER_MANAGER_H_
+#define COMPONENTS_AUTOFILL_CONTENT_BROWSER_KEY_PRESS_HANDLER_MANAGER_H_
+
+#include "base/macros.h"
+#include "content/public/browser/render_widget_host.h"
+
+namespace autofill {
+
+// KeyPressHandlerManager allows registering a key press handler and ensuring
+// its unregistering in case of destruction of the manager or request for
+// registration of another handler. It still needs a Delegate implementation to
+// use the low-level handler registration API.
+
+class KeyPressHandlerManager {
+ public:
+  class Delegate {
+   public:
+    virtual void AddHandler(
+        const content::RenderWidgetHost::KeyPressEventCallback& handler) = 0;
+    virtual void RemoveHandler(
+        const content::RenderWidgetHost::KeyPressEventCallback& handler) = 0;
+  };
+
+  explicit KeyPressHandlerManager(Delegate* delegate);
+
+  virtual ~KeyPressHandlerManager();
+
+  void RegisterKeyPressHandler(
+      const content::RenderWidgetHost::KeyPressEventCallback& handler);
+
+  void RemoveKeyPressHandler();  // Unregisters previous handler.
+
+ private:
+  Delegate* const delegate_;
+
+  content::RenderWidgetHost::KeyPressEventCallback handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(KeyPressHandlerManager);
+};
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_CONTENT_BROWSER_KEY_PRESS_HANDLER_MANAGER_H_