[Set Window Rect] Why result is integral & round down

[yezhizhen]

Continuing from #1909 (comment).
Based on test expectation, the set parameter can be floats. But the result is expected to floor down to integer.

The question is:

1. Why should the result be integral? https://github.com/web-platform-tests/wpt/blob/7da2887747da3ae5215b88e22d61a0fb69e13acb/webdriver/tests/classic/set_window_rect/set.py#L41
2. Why do we round down? https://github.com/web-platform-tests/wpt/blob/7da2887747da3ae5215b88e22d61a0fb69e13acb/webdriver/tests/classic/set_window_rect/set.py#L160

It seems neither is specified in Spec.

[whimboo]

When I check the definition on the Window interface I cannot see that the values can be float. They are defined as:

 [Replaceable] readonly attribute long outerWidth;
 [Replaceable] readonly attribute long outerHeight;

@jgraham why do you think that those can be float? Note that also window.moveBy() only accepts long and no float. So basically the browser should internally round the value so that no float is returned.