Refactor backdrop that is currently used in the maximized mode.

components/exo/BUILD.gn

 # Copyright 2015 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/ui.gni")
 import("//testing/test.gni")
 
 source_set("exo") {
   sources = [
     "buffer.cc",
@@ skipping 108 matching lines @@
     "sub_surface_unittest.cc",
     "surface_unittest.cc",
     "touch_unittest.cc",
   ]
 
   deps = [
     ":exo",
     ":test_support",
     "//ash",
     "//ash/public/cpp:ash_public_cpp",
+    "//ash/test:test_support_without_content",
     "//base",
     "//base/test:test_support",
     "//cc",
     "//cc:test_support",
     "//cc/surfaces:surfaces",
     "//components/user_manager",
     "//device/gamepad:test_helpers",
     "//gpu/command_buffer/client:gles2_interface",
     "//skia",
     "//testing/gmock",
@@ skipping 38 matching lines @@
   data_deps = [
     "//ash/strings:ash_test_strings",
     "//ash/resources:ash_test_resources_100_percent",
     "//ash/resources:ash_test_resources_200_percent",
   ]
 
   if (is_linux) {
     deps += [ "//components/exo/wayland:unit_tests" ]
   }
 }