Clean up the IncludeBetaForumMenuItem feature.

The feature was added here: https://codereview.chromium.org/2882013002.

Bug: 1126640
Change-Id: Ie5d20b449c5144b1fbf163a6e0947cdd52dca56f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2427030Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#815371}

chrome/browser/ui/toolbar/app_menu_model.cc

@@ -168,9 +168,6 @@ void ZoomMenuModel::Build() {
 // HelpMenuModel
 // Only used in branded builds.
 
-const base::Feature kIncludeBetaForumMenuItem{
-    "IncludeBetaForumMenuItem", base::FEATURE_DISABLED_BY_DEFAULT};
-
 class HelpMenuModel : public ui::SimpleMenuModel {
  public:
   HelpMenuModel(ui::SimpleMenuModel::Delegate* delegate, Browser* browser)
@@ -191,8 +188,6 @@ class HelpMenuModel : public ui::SimpleMenuModel {
     AddItem(IDC_ABOUT, l10n_util::GetStringUTF16(IDS_ABOUT));
 #endif
     AddItemWithStringId(IDC_HELP_PAGE_VIA_MENU, help_string_id);
-    if (base::FeatureList::IsEnabled(kIncludeBetaForumMenuItem))
-      AddItem(IDC_SHOW_BETA_FORUM, l10n_util::GetStringUTF16(IDS_BETA_FORUM));
     if (browser_defaults::kShowHelpMenuItemIcon) {
       ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
       SetIcon(GetIndexOfCommandId(IDC_HELP_PAGE_VIA_MENU),

testing/variations/fieldtrial_testing_config.json

@@ -3532,24 +3532,6 @@
             ]
         }
     ],
-    "IncludeBetaForumMenuItem": [
-        {
-            "platforms": [
-                "chromeos",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "IncludeBetaForumMenuItem"
-                    ]
-                }
-            ]
-        }
-    ],
     "IncompatibleApplicationsWarning": [
         {
             "platforms": [