Allow tab accelerators for system apps

Browser type app can also support tabs and should allow
tab accelerators (select next tab, select tab N, etc)
when tabs are being used.

Browser::SupportsFeatures(Browser::FEATURE_TABSTRIP) provides
the logic to detect when tabs are supported.

Bug: 1033334
Change-Id: I2e97d5d59f3b21233394c3c382fdc1fcefae3438
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2062022
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742869}

chrome/browser/ui/browser_command_controller.cc

@@ -1035,20 +1035,22 @@ void BrowserCommandController::InitCommandState() {
   command_updater_.UpdateCommandEnabled(IDC_SITE_SETTINGS, is_web_app);
   command_updater_.UpdateCommandEnabled(IDC_WEB_APP_MENU_APP_INFO, is_web_app);
 
-  // Window management commands
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_NEXT_TAB, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_PREVIOUS_TAB, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_MOVE_TAB_NEXT, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_MOVE_TAB_PREVIOUS, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_0, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_1, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_2, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_3, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_4, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_5, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_6, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_7, normal_window);
-  command_updater_.UpdateCommandEnabled(IDC_SELECT_LAST_TAB, normal_window);
+  // Tab management commands
+  const bool supports_tabs =
+      browser_->SupportsWindowFeature(Browser::FEATURE_TABSTRIP);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_NEXT_TAB, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_PREVIOUS_TAB, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_MOVE_TAB_NEXT, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_MOVE_TAB_PREVIOUS, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_0, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_1, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_2, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_3, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_4, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_5, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_6, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_TAB_7, supports_tabs);
+  command_updater_.UpdateCommandEnabled(IDC_SELECT_LAST_TAB, supports_tabs);
 
   // These are always enabled; the menu determines their menu item visibility.
   command_updater_.UpdateCommandEnabled(IDC_UPGRADE_DIALOG, true);