WMF: re-enabled video probes and made it more robust.

Fixed the way the custom MF Transform (getting the frames) works:
- Recreate it whenever we load a new media
- During media type negotiation between nodes, the MFT should support
  the same types as the video sink supports
- Allow input and output types to be changed as many times as needed,
  otherwise the topology cannot be resolved in some cases

Change-Id: I7ca77e1a3dee83643f1a97f2e6ada9c5c0e88309
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

src/plugins/wmf/mftvideo.h

@@ -61,6 +61,8 @@ public:
     void addProbe(MFVideoProbeControl* probe);
     void removeProbe(MFVideoProbeControl* probe);
 
+    void addSupportedMediaType(IMFMediaType *type);
+
     // IUnknown methods
     STDMETHODIMP QueryInterface(REFIID iid, void** ppv);
     STDMETHODIMP_(ULONG) AddRef();
@@ -97,6 +99,7 @@ private:
     static QVideoSurfaceFormat videoFormatForMFMediaType(IMFMediaType *mediaType, int *bytesPerLine);
     QVideoFrame makeVideoFrame();
     QByteArray dataFromBuffer(IMFMediaBuffer *buffer, int height, int *bytesPerLine);
+    bool isMediaTypeSupported(IMFMediaType *type);
 
     long m_cRef;
     IMFMediaType *m_inputType;
@@ -104,6 +107,8 @@ private:
     IMFSample *m_sample;
     QMutex m_mutex;
 
+    QList<IMFMediaType*> m_mediaTypes;
+
     QList<MFVideoProbeControl*> m_videoProbes;
     QMutex m_videoProbeMutex;