Move a bunch of ash-only vector icons to ash/.

ui/gfx/vector_icons/system_menu_brightness.icon

Index: ui/gfx/vector_icons/system_menu_brightness.icon
diff --git a/ui/gfx/vector_icons/system_menu_brightness.icon b/ui/gfx/vector_icons/system_menu_brightness.icon
deleted file mode 100644
index fdb50dc6d43e0f33bae43b227986763377562dba..0000000000000000000000000000000000000000
--- a/ui/gfx/vector_icons/system_menu_brightness.icon
+++ /dev/null
@@ -1,34 +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, 40,
-MOVE_TO, 31, 9,
-R_H_LINE_TO, -6,
-R_LINE_TO, -5, -5,
-R_LINE_TO, -5, 5,
-H_LINE_TO, 9,
-R_V_LINE_TO, 6,
-R_LINE_TO, -5, 5,
-R_LINE_TO, 5, 5,
-R_V_LINE_TO, 6,
-R_H_LINE_TO, 6,
-R_LINE_TO, 5, 5,
-R_LINE_TO, 5, -5,
-R_H_LINE_TO, 6,
-R_V_LINE_TO, -6,
-R_LINE_TO, 5, -5,
-R_LINE_TO, -5, -5,
-V_LINE_TO, 9,
-CLOSE,
-MOVE_TO, 20, 28,
-R_CUBIC_TO, -4.41f, 0, -8, -3.59f, -8, -8,
-R_CUBIC_TO, 0, -4.41f, 3.59f, -8, 8, -8,
-R_CUBIC_TO, 4.41f, 0, 8, 3.59f, 8, 8,
-R_CUBIC_TO, 0, 4.41f, -3.59f, 8, -8, 8,
-CLOSE,
-R_MOVE_TO, 0, -2,
-R_ARC_TO, 6, 6, 0, 1, 0, 0, -12,
-R_ARC_TO, 6, 6, 0, 0, 0, 0, 12,
-CLOSE,
-END