Move InfoBarResponder into its own file.

chrome/browser/infobars/infobar_responder.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_INFOBARS_INFOBAR_RESPONDER_H_
+#define CHROME_BROWSER_INFOBARS_INFOBAR_RESPONDER_H_
+
+#include "base/macros.h"
+#include "components/infobars/core/infobar_manager.h"
+
+namespace infobars {
+class InfoBar;
+}
+
+class ConfirmInfoBarDelegate;
+class InfoBarService;
+
+// Used by test code to asynchronously respond to the first infobar shown, which
+// must have a ConfirmInfoBarDelegate. This can be used to ensure various
+// interaction flows work correctly.
+//
+// The asynchronous response matches how real users will use the infobar.
+class InfoBarResponder : public infobars::InfoBarManager::Observer {
+ public:
+  // If |should_accept| is true, the responder will asynchronously Accept() the
+  // infobar; otherwise it will Cancel() it.
+  InfoBarResponder(InfoBarService* infobar_service, bool should_accept);
+  ~InfoBarResponder() override;
+
+  // infobars::InfoBarManager::Observer:
+  void OnInfoBarAdded(infobars::InfoBar* infobar) override;
+
+ private:
+  void Respond(ConfirmInfoBarDelegate* delegate);
+
+  InfoBarService* infobar_service_;
+  bool should_accept_;
+
+  DISALLOW_COPY_AND_ASSIGN(InfoBarResponder);
+};
+
+#endif  // CHROME_BROWSER_INFOBARS_INFOBAR_RESPONDER_H_