offscreen plugin: eradicate Q_FOREACH loops

... by replacing them with C++11 for-each loops.

In clearHash(), replace iteration over QHash::keys() with
iteration over the hash itself. Also use the new const-
iterator overload of QHash::erase() to save one attempted
detach (in QHash::find()).

Mark the plugin as QT_NO_FOREACH.

Saves almost 2KiB (1.4%) in text size on optimized GCC 6.1 Linux
AMD64 builds.

Change-Id: I9bb3154130687c0061ea09b04ab5f627a4d2296c
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

src/plugins/platforms/offscreen/offscreen.pro

@@ -2,6 +2,8 @@ TARGET = qoffscreen
 
 QT += core-private gui-private platformsupport-private
 
+DEFINES += QT_NO_FOREACH
+
 SOURCES =   main.cpp \
             qoffscreenintegration.cpp \
             qoffscreenwindow.cpp \

src/plugins/platforms/offscreen/qoffscreencommon.cpp

@@ -59,9 +59,9 @@ public:
     void setPos(const QPoint &pos) Q_DECL_OVERRIDE
     {
         m_pos = pos;
-        QWindowList wl = QGuiApplication::topLevelWindows();
+        const QWindowList wl = QGuiApplication::topLevelWindows();
         QWindow *containing = 0;
-        foreach (QWindow *w, wl) {
+        for (QWindow *w : wl) {
             if (w->type() != Qt::Desktop && w->isExposed() && w->geometry().contains(pos)) {
                 containing = w;
                 break;
@@ -104,9 +104,9 @@ QPixmap QOffscreenScreen::grabWindow(WId id, int x, int y, int width, int height
 
     QOffscreenWindow *window = QOffscreenWindow::windowForWinId(id);
     if (!window || window->window()->type() == Qt::Desktop) {
-        QWindowList wl = QGuiApplication::topLevelWindows();
+        const QWindowList wl = QGuiApplication::topLevelWindows();
         QWindow *containing = 0;
-        foreach (QWindow *w, wl) {
+        for (QWindow *w : wl) {
             if (w->type() != Qt::Desktop && w->isExposed() && w->geometry().contains(rect)) {
                 containing = w;
                 break;
@@ -212,11 +212,10 @@ QOffscreenBackingStore *QOffscreenBackingStore::backingStoreForWinId(WId id)
 
 void QOffscreenBackingStore::clearHash()
 {
-    QList<WId> ids = m_windowAreaHash.keys();
-    foreach (WId id, ids) {
-        QHash<WId, QOffscreenBackingStore *>::iterator it = m_backingStoreForWinIdHash.find(id);
-        if (it.value() == this)
-            m_backingStoreForWinIdHash.remove(id);
+    for (auto it = m_windowAreaHash.cbegin(), end = m_windowAreaHash.cend(); it != end; ++it) {
+        const auto it2 = qAsConst(m_backingStoreForWinIdHash).find(it.key());
+        if (it2.value() == this)
+            m_backingStoreForWinIdHash.erase(it2);
     }
     m_windowAreaHash.clear();
 }