Drop ReleaseReason enum

src/window.h

@@ -55,15 +55,6 @@ class SurfaceItem;
 class VirtualDesktop;
 class WindowItem;
 
-/**
- * Enum to describe the reason why a Window has to be released.
- */
-enum class ReleaseReason {
-    Release, ///< Normal Release after e.g. an Unmap notify event (window still valid)
-    Destroyed, ///< Release after an Destroy notify event (window no longer valid)
-    KWinShutsDown ///< Release on KWin Shutdown (window still valid)
-};
-
 namespace Decoration
 {
 class DecoratedClientImpl;