Fix repainting of Shadows for torn-off toolbars

Toolbars and Dock Widgets are clients which did not yet have
proper Shadow support. Especially the visibleRect and decorationRect
which is incorrectly used to refer to the complete window geometry
had to be updated.

client.cpp

@@ -44,6 +44,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "notifications.h"
 #include "rules.h"
 #include "scene.h"
+#include "shadow.h"
 #include "deleted.h"
 #include "paintredirector.h"
 #include "tabbox.h"
@@ -2239,6 +2240,17 @@ void Client::setSessionInteract(bool needed)
     needsSessionInteract = needed;
 }
 
+QRect Client::decorationRect() const
+{
+    if (decoration && decoration->widget()) {
+        return decoration->widget()->rect().translated(-padding_left, -padding_top);
+    } else if (hasShadow()) {
+        return shadow()->shadowRegion().boundingRect();
+    } else {
+        return QRect(0, 0, width(), height());
+    }
+}
+
 } // namespace
 
 #include "client.moc"

client.h

@@ -401,11 +401,7 @@ public:
     bool decorationPixmapRequiresRepaint();
     void ensureDecorationPixmapsPainted();
 
-    QRect decorationRect() const {
-        return (decoration && decoration->widget()) ?
-               decoration->widget()->rect().translated(-padding_left, -padding_top) :
-               QRect(0, 0, width(), height());
-    }
+    QRect decorationRect() const;
 
     QRect transparentRect() const;
 
@@ -967,7 +963,7 @@ inline QSize Client::clientSize() const
 
 inline QRect Client::visibleRect() const
 {
-    return geometry().adjusted(-padding_left, -padding_top, padding_right, padding_bottom);
+    return Toplevel::visibleRect().adjusted(-padding_left, -padding_top, padding_right, padding_bottom);
 }
 
 inline void Client::setGeometry(const QRect& r, ForceGeometry_t force, bool emitJs)