Properly handle the case where QtWidgets is not available.

It does use a config test for now, just to make it clearer.  The Mac
backend currently requires widgets, but most of the others should work
without it (just not supporting QVideoWidget/WindowControl).

The QVideoDeviceControl interface was modified to remove the QIcon
usage - it was never implemented.

Unfortunately even the QML examples need widgets for the wrapper
application, and will need to be ported to QtGui based wrapper.

Change-Id: I8a55ad5cf09ab51749510bf16f49de0bd3f0bcdb
Reviewed-by: Ling Hu <ling.hu@nokia.com>

src/plugins/qt7/qt7.pro

@@ -1,7 +1,11 @@
 load(qt_module)
 
 TARGET = qqt7engine
-QT += multimedia-private multimediawidgets-private network widgets
+QT += multimedia-private network
+contains(config_test_widgets, yes) {
+    QT += multimediawidgets-private widgets
+}
+
 PLUGIN_TYPE = mediaservice
 
 load(qt_plugin)
@@ -39,7 +43,6 @@ OBJECTIVE_SOURCES += \
 !simulator {
     HEADERS += \
         qt7movieviewoutput.h \
-        qt7movievideowidget.h \
         qt7movieviewrenderer.h \
         qt7movierenderer.h \
         qt7ciimagevideobuffer.h \
@@ -47,12 +50,19 @@ OBJECTIVE_SOURCES += \
 
     OBJECTIVE_SOURCES += \
         qt7movieviewoutput.mm \
-        qt7movievideowidget.mm \
         qt7movieviewrenderer.mm \
         qt7movierenderer.mm \
         qt7videooutput.mm \
         qt7ciimagevideobuffer.mm \
         qcvdisplaylink.mm
+
+    contains(config_test_widgets, yes) {
+        HEADERS += \
+            qt7movieviewwidget.h
+
+        OBJECTIVE_SOURCES += \
+            qt7movievideowidget.mm
+    }
 }
 
 include(mediaplayer/mediaplayer.pri)