Remove most_recently_raised micro optimization

This micro optimization is simply not worth having. raiseOrLowerClient()
is not in any hot path, besides that raiseClient() is not the only place
where a window can be raised above other windows. In addition to that,
the most_recently_raised check in raiseOrLowerClient() doesn't take into
account whether the cached window is on the current activity.

src/layers.cpp

@@ -277,13 +277,8 @@ AbstractClient* Workspace::findDesktop(bool topmost, int desktop) const
 void Workspace::raiseOrLowerClient(AbstractClient *c)
 {
     if (!c) return;
-    AbstractClient* topmost = nullptr;
+    const AbstractClient *topmost =
-// TODO    Q_ASSERT( block_stacking_updates == 0 );
+            topClientOnDesktop(c->isOnAllDesktops() ? VirtualDesktopManager::self()->current() : c->desktop(),
-    if (most_recently_raised && stacking_order.contains(most_recently_raised) &&
-            most_recently_raised->isShown(true) && c->isOnCurrentDesktop())
-        topmost = most_recently_raised;
-    else
-        topmost = topClientOnDesktop(c->isOnAllDesktops() ? VirtualDesktopManager::self()->current() : c->desktop(),
                                options->isSeparateScreenFocus() ? c->screen() : -1);
 
     if (c == topmost)
@@ -317,9 +312,6 @@ void Workspace::lowerClient(AbstractClient* c, bool nogroup)
                 lowerClient(wins[ i ], true);
         }
     }
-
-    if (c == most_recently_raised)
-        most_recently_raised = nullptr;
 }
 
 void Workspace::lowerClientWithinApplication(AbstractClient* c)
@@ -372,10 +364,6 @@ void Workspace::raiseClient(AbstractClient* c, bool nogroup)
 
     unconstrained_stacking_order.removeAll(c);
     unconstrained_stacking_order.append(c);
-
-    if (!c->isSpecialWindow()) {
-        most_recently_raised = c;
-    }
 }
 
 void Workspace::raiseClientWithinApplication(AbstractClient* c)

src/workspace.cpp

@@ -114,7 +114,6 @@ Workspace::Workspace()
     , m_initialDesktop(1)
     , active_client(nullptr)
     , last_active_client(nullptr)
-    , most_recently_raised(nullptr)
     , movingClient(nullptr)
     , delayfocus_client(nullptr)
     , force_restacking(false)
@@ -650,8 +649,6 @@ void Workspace::removeClient(X11Client *c)
     if (group != nullptr)
         group->lostLeader();
 
-    if (c == most_recently_raised)
-        most_recently_raised = nullptr;
     should_get_focus.removeAll(c);
     if (c == active_client)
         active_client = nullptr;
@@ -768,9 +765,6 @@ void Workspace::removeShellClient(AbstractClient *client)
 {
     clientHidden(client);
     m_allClients.removeAll(client);
-    if (client == most_recently_raised) {
-        most_recently_raised = nullptr;
-    }
     if (client == delayfocus_client) {
         cancelDelayFocus();
     }

src/workspace.h

@@ -576,7 +576,6 @@ private:
 
     AbstractClient* active_client;
     AbstractClient* last_active_client;
-    AbstractClient* most_recently_raised; // Used ONLY by raiseOrLowerClient()
     AbstractClient* movingClient;
 
     // Delay(ed) window focus timer and client