aSize = PR_ROUNDUP(aSize, 4);
aSize = PR_ROUNDUP(aSize, sizeof(void*));
FrameArena::AllocateFrame(size_t aSize, void** aResult){  void* result = nsnull;    // Round size to multiple of 4  aSize = PR_ROUNDUP(aSize, 4);  // Check recyclers first  if (aSize < gMaxRecycledSize) {    const int   index = aSize >> 2;    result = mRecyclers[index];    if (result) {      // Need to move to the next object      void* next = *((void**)result);      mRecyclers[index] = next;    }  }  if (!result) {    // Allocate a new chunk from the arena    PL_ARENA_ALLOCATE(result, &mPool, aSize);  }  *aResult = result;  return NS_OK;}