[merge to m60] cros: Do not cache |root_window| in ScreenRotationAnimator.

ash/display/display_configuration_controller_unittest.cc

 // 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.
 
 #include "ash/public/cpp/config.h"
 #include "ash/rotator/screen_rotation_animator.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/display_configuration_controller_test_api.h"
 #include "base/macros.h"
 #include "ui/display/manager/display_manager.h"
 
 namespace ash {
 
 using DisplayConfigurationControllerTest = test::AshTestBase;
 
 TEST_F(DisplayConfigurationControllerTest, OnlyHasOneAnimator) {
   // TODO(wutao): needs display_configuration_controller
   // http://crbug.com/686839.
   if (Shell::GetAshConfig() == Config::MASH)
     return;
 
   display::Display display = display::Screen::GetScreen()->GetPrimaryDisplay();
   test::DisplayConfigurationControllerTestApi testapi(
       Shell::Get()->display_configuration_controller());
-  ScreenRotationAnimator* screen_rotation_animator =
+  ScreenRotationAnimator* old_screen_rotation_animator =
       testapi.GetScreenRotationAnimatorForDisplay(display.id());
-  EXPECT_EQ(1, testapi.DisplayScreenRotationAnimatorMapSize());
 
   Shell::Get()->display_manager()->SetDisplayRotation(
       display.id(), display::Display::ROTATE_0,
       display::Display::RotationSource::ROTATION_SOURCE_USER);
-  screen_rotation_animator->Rotate(
+  old_screen_rotation_animator->Rotate(
       display::Display::ROTATE_90,
       display::Display::RotationSource::ROTATION_SOURCE_USER);
-  EXPECT_EQ(1, testapi.DisplayScreenRotationAnimatorMapSize());
 
-  screen_rotation_animator =
+  ScreenRotationAnimator* new_screen_rotation_animator =
       testapi.GetScreenRotationAnimatorForDisplay(display.id());
-  screen_rotation_animator->Rotate(
+  new_screen_rotation_animator->Rotate(
       display::Display::ROTATE_180,
       display::Display::RotationSource::ROTATION_SOURCE_USER);
-  EXPECT_EQ(1, testapi.DisplayScreenRotationAnimatorMapSize());
+  EXPECT_EQ(old_screen_rotation_animator, new_screen_rotation_animator);
 }
 
 }  // namespace ash