🏠 Add expand button and flag to enable it

chrome/browser/flag_descriptions.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 CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 #define CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 
 // Includes needed for macros allowing conditional compilation of some strings.
 #include "build/build_config.h"
 #include "build/buildflag.h"
@@ skipping 2160 matching lines @@
 //  Chrome home flags
 
 #if defined(OS_ANDROID)
 
 // The name of the Chrome Home experiment in about:flags.
 extern const char kChromeHomeName[];
 
 // Description of the Chrome Home experiment in about:flags.
 extern const char kChromeHomeDescription[];
 
+// The name of the Chrome Home expand button experiment in about:flags.
+extern const char kChromeHomeExpandButtonName[];
+
+// Description of the Chrome Home expand button experiment in about:flags.
+extern const char kChromeHomeExpandButtonDescription[];
+
 #endif  // defined(OS_ANDROID)
 
 //  In-Product Help flags
 
 #if defined(OS_ANDROID)
 
 // The name of the In-Product Help demo mode in about:flags.
 extern const char kEnableIphDemoMode[];
 
 // Description of the In-Product Help demo mode in about:flags.
@@ skipping 1121 matching lines @@
 // current URL.
 extern const char kOmniboxDisplayTitleForCurrentUrlName[];
 
 // Description of the about: flag for displaying the title of the omnibox match
 // for current URL.
 extern const char kOmniboxDisplayTitleForCurrentUrlDescription[];
 
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_