cros: Remove some OS platform ifdefs from ash

ash/app_list/app_list_presenter_delegate.cc

Index: ash/app_list/app_list_presenter_delegate.cc
diff --git a/ash/app_list/app_list_presenter_delegate.cc b/ash/app_list/app_list_presenter_delegate.cc
index 973875b93c5f3838c2787858714ccec8ffc67b6f..a4a03eab15701812ce10dd6ee3715ae522ba631f 100644
--- a/ash/app_list/app_list_presenter_delegate.cc
+++ b/ash/app_list/app_list_presenter_delegate.cc
@@ -61,12 +61,8 @@ gfx::Point GetCenterOfDisplayForWindow(WmWindow* window, int minimum_height) {
 }
 
 bool IsFullscreenAppListEnabled() {
-#if defined(OS_CHROMEOS)
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kAshEnableFullscreenAppList);
-#else
-  return false;
-#endif
 }
 
 }  // namespace