cros: Remove some OS platform ifdefs from ash

ash/system/overview/overview_button_tray_unittest.cc

Index: ash/system/overview/overview_button_tray_unittest.cc
diff --git a/ash/system/overview/overview_button_tray_unittest.cc b/ash/system/overview/overview_button_tray_unittest.cc
index 7e13d9f90186152ea251ccd63f9d7707e12a4ca0..dd8c308da64449b1167f5e82acee9b3b3c04b9ee 100644
--- a/ash/system/overview/overview_button_tray_unittest.cc
+++ b/ash/system/overview/overview_button_tray_unittest.cc
@@ -212,13 +212,7 @@ TEST_F(OverviewButtonTrayTest, ActiveStateOnlyDuringOverviewMode) {
 
 // Test that when a hide animation is aborted via deletion, that the
 // OverviewButton is still hidden.
-#if defined(OS_WIN) && !defined(USE_ASH)
-// TODO(msw): Broken on Windows. http://crbug.com/584038
-#define MAYBE_HideAnimationAlwaysCompletes DISABLED_HideAnimationAlwaysCompletes
-#else
-#define MAYBE_HideAnimationAlwaysCompletes HideAnimationAlwaysCompletes
-#endif
-TEST_F(OverviewButtonTrayTest, MAYBE_HideAnimationAlwaysCompletes) {
+TEST_F(OverviewButtonTrayTest, HideAnimationAlwaysCompletes) {
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       true);