a11y: Add a11y information to views::Tab and manually ignore its a11y children.

ui/views/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
 import("//ui/ozone/ozone.gni")
 
@@ skipping 827 matching lines @@
     "controls/native/native_view_host_mac_unittest.mm",
     "controls/native/native_view_host_test_base.cc",
     "controls/native/native_view_host_test_base.h",
     "controls/native/native_view_host_unittest.cc",
     "controls/prefix_selector_unittest.cc",
     "controls/progress_bar_unittest.cc",
     "controls/scroll_view_unittest.cc",
     "controls/scrollbar/scrollbar_unittest.cc",
     "controls/slider_unittest.cc",
     "controls/styled_label_unittest.cc",
+    "controls/tabbed_pane/tabbed_pane_accessibility_mac_unittest.mm",
     "controls/tabbed_pane/tabbed_pane_unittest.cc",
     "controls/table/table_utils_unittest.cc",
     "controls/table/table_view_unittest.cc",
     "controls/table/test_table_model.cc",
     "controls/table/test_table_model.h",
     "controls/textfield/textfield_model_unittest.cc",
     "controls/tree/tree_view_unittest.cc",
     "event_monitor_unittest.cc",
     "focus/focus_manager_unittest.cc",
     "focus/focus_traversal_unittest.cc",
@@ skipping 163 matching lines @@
       "//ui/base:test_support",
       "//ui/compositor",
       "//ui/events:test_support",
       "//ui/gl:test_support",
       "//ui/resources",
       "//ui/resources:ui_test_pak",
       "//ui/strings",
     ]
   }
 }