avmedia: call resize before player window is created

Since b5529c8c457f442bfc43305becc0c02d6a09ee80
MediaChildWindow is depend on the media URL so
it is constructed later and so one resizing is
missed before creating the player window which
causes to display nothing in the media player
(Tools -> Media Player)

Change-Id: I548e6bb73193fccd1735e8343e9c06428ee686bc