PerFrameData* pfd = mFrames; while (nsnull != pfd) { PerFrameData* next = pfd->mNext;
for (PerFrameData *next, *pfd = mFrames; pfd; pfd = next) { next = pfd->mNext;
nsFrameImageLoader::~nsFrameImageLoader(){  PerFrameData* pfd = mFrames;  while (nsnull != pfd) {    PerFrameData* next = pfd->mNext;    delete pfd;    pfd = next;  }  NS_IF_RELEASE(mImageRequest);  NS_IF_RELEASE(mPresContext);  NS_IF_RELEASE(mImage);}