Add a client property to ThumbnailItem

Makes it a little bit easier to use a ThumbnailItem for a Client. E.g.
ThumbnailItem {
    client: model.client
}

instead of mapping the windowIds, which is rather uncomfty.

thumbnailitem.cpp

@@ -36,6 +36,7 @@ namespace KWin
 ThumbnailItem::ThumbnailItem(QDeclarativeItem* parent)
     : QDeclarativeItem(parent)
     , m_wId(0)
+    , m_client(NULL)
     , m_clip(true)
     , m_parent(QWeakPointer<EffectWindowImpl>())
     , m_parentWindow(0)
@@ -108,10 +109,33 @@ void ThumbnailItem::findParentEffectWindow()
 
 void ThumbnailItem::setWId(qulonglong wId)
 {
+    if (m_wId == wId) {
+        return;
+    }
     m_wId = wId;
+    if (m_wId != 0) {
+        setClient(Workspace::self()->findClient(WindowMatchPredicate(m_wId)));
+    } else if (m_client) {
+        m_client = NULL;
+        emit clientChanged();
+    }
     emit wIdChanged(wId);
 }
 
+void ThumbnailItem::setClient(Client *client)
+{
+    if (m_client == client) {
+        return;
+    }
+    m_client = client;
+    if (m_client) {
+        setWId(m_client->window());
+    } else {
+        setWId(0);
+    }
+    emit clientChanged();
+}
+
 void ThumbnailItem::setClip(bool clip)
 {
     m_clip = clip;

thumbnailitem.h

@@ -27,6 +27,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 namespace KWin
 {
 
+class Client;
 class EffectWindow;
 class EffectWindowImpl;
 
@@ -38,6 +39,7 @@ class ThumbnailItem : public QDeclarativeItem
     Q_PROPERTY(qulonglong parentWindow READ parentWindow WRITE setParentWindow)
     Q_PROPERTY(qreal brightness READ brightness WRITE setBrightness NOTIFY brightnessChanged)
     Q_PROPERTY(qreal saturation READ saturation WRITE setSaturation NOTIFY saturationChanged)
+    Q_PROPERTY(KWin::Client *client READ client WRITE setClient NOTIFY clientChanged)
 public:
     explicit ThumbnailItem(QDeclarativeItem *parent = 0);
     virtual ~ThumbnailItem();
@@ -57,6 +59,8 @@ public:
     void setParentWindow(qulonglong parentWindow);
     qreal brightness() const;
     qreal saturation() const;
+    Client *client() const;
+    void setClient(Client *client);
 
 public Q_SLOTS:
     void setBrightness(qreal brightness);
@@ -67,6 +71,7 @@ Q_SIGNALS:
     void clipChanged(bool clipped);
     void brightnessChanged();
     void saturationChanged();
+    void clientChanged();
 private Q_SLOTS:
     void init();
     void effectWindowAdded();
@@ -75,6 +80,7 @@ private Q_SLOTS:
 private:
     void findParentEffectWindow();
     qulonglong m_wId;
+    Client *m_client;
     bool m_clip;
     QWeakPointer<EffectWindowImpl> m_parent;
     qulonglong m_parentWindow;
@@ -94,6 +100,12 @@ qreal ThumbnailItem::saturation() const
     return m_saturation;
 }
 
+inline
+Client *ThumbnailItem::client() const
+{
+    return m_client;
+}
+
 } // KWin
 
 #endif // KWIN_THUMBNAILITEM_H