Remove --ash-disable-overview-mode

ash/ash_switches.h

Index: ash/ash_switches.h
diff --git a/ash/ash_switches.h b/ash/ash_switches.h
index 7cae7aa45282fc73f19f99961cf3c93fa259c654..7136c476b6abc58463fd11894ba57206e7cbcf0b 100644
--- a/ash/ash_switches.h
+++ b/ash/ash_switches.h
@@ -27,7 +27,6 @@ ASH_EXPORT extern const char kAshDefaultWallpaperSmall[];
 ASH_EXPORT extern const char kAshDisableAlternateFrameCaptionButtonStyle[];
 ASH_EXPORT extern const char kAshDisableAlternateShelfLayout[];
 ASH_EXPORT extern const char kAshDisableDockedWindows[];
-ASH_EXPORT extern const char kAshDisableOverviewMode[];
 ASH_EXPORT extern const char kAshEnableAdvancedGestures[];
 ASH_EXPORT extern const char kAshEnableAlternateFrameCaptionButtonStyle[];
 ASH_EXPORT extern const char kAshEnableBrightnessControl[];
@@ -68,9 +67,6 @@ ASH_EXPORT bool UseDragOffShelf();
 // immersive fullscreen via <F4>.
 ASH_EXPORT bool UseImmersiveFullscreenForAllWindows();
 
-// Returns true if overview mode should be activated for window switching.
-ASH_EXPORT bool UseOverviewMode();
-
 // Returns true if docked windows feature is enabled.
 ASH_EXPORT bool UseDockedWindows();