views: remove PlatformStyle combobox hooks

ui/views/vector_icons/combobox_arrow_mac_enabled.icon

Index: ui/views/vector_icons/combobox_arrow_mac_enabled.icon
diff --git a/ui/views/vector_icons/combobox_arrow_mac_enabled.icon b/ui/views/vector_icons/combobox_arrow_mac_enabled.icon
deleted file mode 100644
index cf4519e956ff6f2b28df2d16eead683e11219644..0000000000000000000000000000000000000000
--- a/ui/views/vector_icons/combobox_arrow_mac_enabled.icon
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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.
-
-CANVAS_DIMENSIONS, 30,
-
-// The outer layer of the arrows is drawn in transparent-ish solid blue.
-STROKE, 3.5,
-PATH_COLOR_ARGB, 0x40, 0x00, 0x00, 0xff,
-MOVE_TO, 11, 12,
-LINE_TO, 15, 8,
-LINE_TO, 19, 12,
-MOVE_TO, 11, 18,
-LINE_TO, 15, 22,
-LINE_TO, 19, 18,
-
-// The inner layer is a narrower stroke of solid white.
-NEW_PATH,
-STROKE, 2,
-PATH_COLOR_ARGB, 0xff, 0xff, 0xff, 0xff,
-MOVE_TO, 11, 12,
-LINE_TO, 15, 8,
-LINE_TO, 19, 12,
-MOVE_TO, 11, 18,
-LINE_TO, 15, 22,
-LINE_TO, 19, 18,
-END