Change upgrade menu icon to use circle instead of round-rect & ensure the arrow is white

ui/gfx/vector_icons_sources.gypi

 # Copyright 2016 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.
 
 {
   'variables': {
     'common': [
       'vector_icons/account_box.icon',
       'vector_icons/account_child_invert.icon',
       'vector_icons/account_circle.icon',
@@ skipping 152 matching lines @@
       'vector_icons/tab_close_hovered_pressed.1x.icon',
       'vector_icons/tab_close_hovered_pressed.icon',
       'vector_icons/tab_close_normal.1x.icon',
       'vector_icons/tab_close_normal.icon',
       'vector_icons/tab_media_capturing.icon',
       'vector_icons/tab_media_recording.icon',
       'vector_icons/tab_usb_connected.1x.icon',
       'vector_icons/tab_usb_connected.icon',
       'vector_icons/tablet.icon',
       'vector_icons/translate.icon',
-      'vector_icons/upgrade_menu_item.icon',
       'vector_icons/videocam.icon',
       'vector_icons/warning.icon',
       'vector_icons/warning_badge.icon',
       'vector_icons/web.icon',
       'vector_icons/window_control_back.1x.icon',
       'vector_icons/window_control_back.icon',
       'vector_icons/window_control_close.1x.icon',
       'vector_icons/window_control_close.icon',
       'vector_icons/window_control_left_snapped.1x.icon',
       'vector_icons/window_control_left_snapped.icon',
       'vector_icons/window_control_maximize.1x.icon',
       'vector_icons/window_control_maximize.icon',
       'vector_icons/window_control_minimize.1x.icon',
       'vector_icons/window_control_minimize.icon',
       'vector_icons/window_control_restore.1x.icon',
       'vector_icons/window_control_restore.icon',
       'vector_icons/window_control_right_snapped.1x.icon',
       'vector_icons/window_control_right_snapped.icon',
       'vector_icons/zoom_minus.icon',
       'vector_icons/zoom_plus.icon',
     ],
   },
 }