Inconsistent screenshot height when height param in resolution modifier is omitted

[michalwronowski]

After switching to chromedriver one of the ways to obtain a full page screenshot is to omit the height attribute in resolution modifier.
After doing so, height of the window is set dynamically to the value of document.body.scrollHeight property.
The problem is that the height is read immediately after the width of the window has been set.
This in worst case scenarios can lead to inconsistencies in window height and in result in screenshot height.

Please consider adding configurable delay between setting the window width and querying the window height.

Discussed solutions include:

1. Configurable "cooldown" in milliseconds which would cause the test to sleep for configured time.
2. Configurable "wait-for-height" algorithm, which would query document.body.scrollHeight in some defined periods of time to check if the document.body.scrollHeight changes. If defined number of samples would match, modifier would use it to set the window height eventually. This solution would require some threshold, either the number of samples or cumulated time of height readings.

Either one of those solutions or both of them could be implemented.