Add experiment for having a "Beta forum" link in the help menu.

chrome/common/url_constants.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.
 
 // Contains constants for known URLs and portions thereof.
 
 #ifndef CHROME_COMMON_URL_CONSTANTS_H_
 #define CHROME_COMMON_URL_CONSTANTS_H_
 
 #include <stddef.h>
@@ skipping 364 matching lines @@
 
 // "Learn more" URL for the Settings API, NTP bubble and other settings bubbles
 // showing which extension is controlling them.
 extern const char kExtensionControlledSettingLearnMoreURL[];
 
 // General help links for Chrome, opened using various actions.
 extern const char kChromeHelpViaKeyboardURL[];
 extern const char kChromeHelpViaMenuURL[];
 extern const char kChromeHelpViaWebUIURL[];
 
+// Link to the forum for Chrome Beta.
+extern const char kChromeBetaForumURL[];
+
 #if defined(OS_CHROMEOS)
 // Accessibility help link for Chrome.
 extern const char kChromeAccessibilityHelpURL[];
 // Accessibility settings link for Chrome.
 extern const char kChromeAccessibilitySettingsURL[];
 // Palette help link for Chrome.
 extern const char kChromePaletteHelpURL[];
 #endif
 
 #if BUILDFLAG(ENABLE_ONE_CLICK_SIGNIN)
@@ skipping 226 matching lines @@
 extern const char kChooserUsbOverviewURL[];
 
 #if defined(OS_CHROMEOS)
 // The URL for EOL notification
 extern const char kEolNotificationURL[];
 #endif
 
 }  // namespace chrome
 
 #endif  // CHROME_COMMON_URL_CONSTANTS_H_