Client: Implement xdg-decoration-unstable-v1 for SSD support

[ChangeLog][QPA plugin] Added client-side support for the
xdg-decoration-unstable-v1 Wayland extension. Qt clients will now let the
compositor draw the window decorations if configured through this extension.

Note: The env var QT_WAYLAND_DISABLE_WINDOWDECORATION is still supported, but
works on a higher level, and for all shell integrations, while xdg-decoration
only works with xdg-shell stable.

Task-number: QTBUG-69746
Change-Id: I9dd0331bbd8d624c6be54ed23ee3b96446d5820d
Reviewed-by: Pier Luigi Fiorini <pierluigi.fiorini@liri.io>

3 files changed, 10 insertions, 1 deletions

diff --git a/src/client/qwaylanddisplay.cpp b/src/client/qwaylanddisplay.cpp
index 40ceafd96..5e67cd3a6 100644
--- a/src/client/qwaylanddisplay.cpp
+++ b/src/client/qwaylanddisplay.cpp
@@ -326,6 +326,13 @@ void QWaylandDisplay::addRegistryListener(RegistryListener listener, void *data)
         (*l.listener)(l.data, mGlobals[i].registry, mGlobals[i].id, mGlobals[i].interface, mGlobals[i].version);
 }
 
+void QWaylandDisplay::removeListener(RegistryListener listener, void *data)
+{
+    std::remove_if(mRegistryListeners.begin(), mRegistryListeners.end(), [=](Listener l){
+        return (l.listener == listener && l.data == data);
+    });
+}
+
 uint32_t QWaylandDisplay::currentTimeMillisec()
 {
     //### we throw away the time information
diff --git a/src/client/qwaylanddisplay_p.h b/src/client/qwaylanddisplay_p.h
index aee1ed45f..8839bbe4c 100644
--- a/src/client/qwaylanddisplay_p.h
+++ b/src/client/qwaylanddisplay_p.h
@@ -161,6 +161,7 @@ public:
     /* wl_registry_add_listener does not add but rather sets a listener, so this function is used
      * to enable many listeners at once. */
     void addRegistryListener(RegistryListener listener, void *data);
+    void removeListener(RegistryListener listener, void *data);
 
     QWaylandShm *shm() const { return mShm.data(); }
 
diff --git a/src/client/qwaylandintegration_p.h b/src/client/qwaylandintegration_p.h
index 8c34e7198..a5a3d7b69 100644
--- a/src/client/qwaylandintegration_p.h
+++ b/src/client/qwaylandintegration_p.h
@@ -117,7 +117,8 @@ public:
     virtual QWaylandShellIntegration *shellIntegration() const;
 
 private:
-    // NOTE: mDisplay *must* be destructed after mDrag and mClientBufferIntegration.
+    // NOTE: mDisplay *must* be destructed after mDrag and mClientBufferIntegration
+    // and mShellIntegration.
     // Do not move this definition into the private section at the bottom.
     QScopedPointer<QWaylandDisplay> mDisplay;