Add an experiment for the default browser infobar on Windows 10

chrome/browser/ui/startup/default_browser_prompt.h

 // Copyright (c) 2012 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_STARTUP_DEFAULT_BROWSER_PROMPT_H_
 #define CHROME_BROWSER_UI_STARTUP_DEFAULT_BROWSER_PROMPT_H_
 
+#include "components/infobars/core/confirm_infobar_delegate.h"
+
 class PrefRegistrySimple;
 class Profile;
 
 namespace chrome {
 
 void RegisterDefaultBrowserPromptPrefs(PrefRegistrySimple* registry);
 
 // Shows a prompt UI to set the default browser if necessary.
 void ShowDefaultBrowserPrompt(Profile* profile);
 
 // Marks the default browser prompt as having been declined.
 void DefaultBrowserPromptDeclined(Profile* profile);
 
 // Resets the tracking preference for the default browser prompt so that it is
 // re-shown if the browser ceases to be the user's chosen default.
 void ResetDefaultBrowserPrompt(Profile* profile);
 
 // Shows a prompt UI to set the default browser on first run
 // (if necessary and permitted). Returns true if the dialog has been launched.
 bool ShowFirstRunDefaultBrowserPrompt(Profile* profile);
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_STARTUP_DEFAULT_BROWSER_PROMPT_H_