[Mac] Touch Bar support for default browser window state

chrome/app/vector_icons/BUILD.gn

 # 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.
 
 import("//ui/vector_icons/vector_icons.gni")
 
 aggregate_vector_icons("chrome_vector_icons") {
   icon_directory = "."
 
   icons = [
@@ skipping 39 matching lines @@
     "tab_close_normal.icon",
     "tab_media_capturing.icon",
     "tab_media_recording.icon",
     "tab_usb_connected.1x.icon",
     "tab_usb_connected.icon",
     "tablet.icon",
     "translate.icon",
     "zoom_minus.icon",
     "zoom_plus.icon",
   ]
+
+  if (is_mac) {
+    icons += [ "new_tab_mac_touchbar.icon" ]
+  }
 }
 
 source_set("vector_icons") {
   sources = get_target_outputs(":chrome_vector_icons")
   sources += [ "//ui/gfx/vector_icon_types.h" ]
 
   deps = [
     ":chrome_vector_icons",
     "//base",
     "//skia",
   ]
 }