kDisabled
int32 key = kDisabled;
if (key == kDisabled)
return kDisabled;
testRight = kDisabled;
if (testLeft == kUnset && (testRight == kUnset || testRight == kDisabled))
right = kDisabled;
if (left == kUnset && (right == kUnset || right == kDisabled))
static const int32 kDisabled = -1;