Re-apply color transforms when session is re-activated

When our session is re-activated, we need to re-apply color transforms
as the current gamma ramps might be outdated.

autotests/integration/kwin_wayland_test.cpp

@@ -128,6 +128,7 @@ void WaylandTestApplication::performStartup()
 
     // first load options - done internally by a different thread
     createOptions();
+    createSession();
     createColorManager();
     waylandServer()->createInternalConnection();
 

colormanager.cpp

@@ -7,6 +7,7 @@
 #include "colormanager.h"
 #include "abstract_output.h"
 #include "colordevice.h"
+#include "logind.h"
 #include "main.h"
 #include "platform.h"
 #include "utils.h"
@@ -28,6 +29,7 @@ ColorManager::ColorManager(QObject *parent)
 {
     connect(kwinApp()->platform(), &Platform::outputEnabled, this, &ColorManager::handleOutputEnabled);
     connect(kwinApp()->platform(), &Platform::outputDisabled, this, &ColorManager::handleOutputDisabled);
+    connect(LogindIntegration::self(), &LogindIntegration::sessionActiveChanged, this, &ColorManager::handleSessionActiveChanged);
 }
 
 ColorManager::~ColorManager()
@@ -73,4 +75,14 @@ void ColorManager::handleOutputDisabled(AbstractOutput *output)
     delete device;
 }
 
+void ColorManager::handleSessionActiveChanged(bool active)
+{
+    if (!active) {
+        return;
+    }
+    for (ColorDevice *device : qAsConst(d->devices)) {
+        device->scheduleUpdate();
+    }
+}
+
 } // namespace KWin

colormanager.h

@@ -52,6 +52,7 @@ Q_SIGNALS:
 private Q_SLOTS:
     void handleOutputEnabled(AbstractOutput *output);
     void handleOutputDisabled(AbstractOutput *output);
+    void handleSessionActiveChanged(bool active);
 
 private:
     QScopedPointer<ColorManagerPrivate> d;

main.cpp

@@ -272,10 +272,14 @@ void Application::createWorkspace()
     emit workspaceCreated();
 }
 
+void Application::createSession()
+{
+    LogindIntegration::create(this);
+}
+
 void Application::createInput()
 {
     ScreenLockerWatcher::create(this);
-    LogindIntegration::create(this);
     auto input = InputRedirection::create(this);
     input->init();
     m_platform->createPlatformCursor(this);

main.h

@@ -207,6 +207,7 @@ protected:
 
     void notifyKSplash();
     void notifyStarted();
+    void createSession();
     void createInput();
     void createWorkspace();
     void createAtoms();

main_wayland.cpp

@@ -149,6 +149,7 @@ void ApplicationWayland::performStartup()
     }
     // first load options - done internally by a different thread
     createOptions();
+    createSession();
     createColorManager();
     waylandServer()->createInternalConnection();
 

main_x11.cpp

@@ -231,6 +231,7 @@ void ApplicationX11::performStartup()
         installNativeX11EventFilter();
         // first load options - done internally by a different thread
         createOptions();
+        createSession();
         createColorManager();
 
         // Check  whether another windowmanager is running