Fixes for -Wunused-function on Linux, Android and ChromeOS

ash/wm/lock_state_controller_unittest.cc

Index: ash/wm/lock_state_controller_unittest.cc
diff --git a/ash/wm/lock_state_controller_unittest.cc b/ash/wm/lock_state_controller_unittest.cc
index 425f4392211389b9d878478c3b3c0360d2ce366f..5290457d212b81d24c439a1d0050240b07d19f2d 100644
--- a/ash/wm/lock_state_controller_unittest.cc
+++ b/ash/wm/lock_state_controller_unittest.cc
@@ -55,14 +55,6 @@ bool IsBackgroundHidden() {
               IsVisible();
 }
 
-void ShowBackground() {
-  ui::ScopedLayerAnimationSettings settings(
-      GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->
-          layer()->GetAnimator());
-  settings.SetTransitionDuration(base::TimeDelta());
-  GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->Show();
-}
-
 void HideBackground() {
   ui::ScopedLayerAnimationSettings settings(
       GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->