Need the ability to find the element through the whole page

[chloechen727]

Currently, pyuia could only find the element in current visible frame but in the whole page.
Need the ability to find the element through the whole page.
Maybe it can find the element while swiping up/ down the pages.

[imsardine]

Although location_once_scrolled_into_view is defined in WebDriver API, it expects, however, the element is available beforehand. The assumption conflicts with a characteristic of UI Automator - only elements visible on the screen are exposed by the API. In contrast, iOS UI Automation expose all elements, including invisible ones. Therefore, we should take the difference in behavior between Android and iOS APIs into account while designing and implementing this feature.