if (aOuter) mOuter = aOuter; else mOuter = &mInner;  mCompletedImages = 0;
if (0 == gNumThrobbers++) { gThrobbers = new nsVoidArray; }
nsThrobber::nsThrobber(nsISupports* aOuter){  // assign outer  if (aOuter)     mOuter = aOuter;  else     mOuter = &mInner;  mCompletedImages = 0;  AddThrobber(this);  mPreferredWidth  = 0;  mPreferredHeight = 0;}