qpa: Merge qwidget_qpa.cpp into qwidget.cpp

Change-Id: I8424ec7290b366f4c76999a956fce1428fc56626
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>

src/widgets/kernel/kernel.pri

@@ -61,7 +61,6 @@ SOURCES += \
         kernel/qdesktopwidget.cpp \
         kernel/qwidgetsvariant.cpp \
         kernel/qapplication_qpa.cpp \
-        kernel/qwidget_qpa.cpp \
         kernel/qwidgetwindow.cpp \
         kernel/qwindowcontainer.cpp
 

src/widgets/kernel/qwidget_p.h

@@ -732,7 +732,7 @@ public:
 
     // *************************** Platform specific ************************************
 #if defined(Q_OS_WIN)
-    uint noPaintOnScreen : 1; // see qwidget_qpa.cpp ::paintEngine()
+    uint noPaintOnScreen : 1; // see qwidget.cpp ::paintEngine()
 #endif
 #if defined(Q_WS_X11) // <----------------------------------------------------------- X11
     Qt::HANDLE picture;