Steps to reproduce the problem:
1. open an app with a webview
2. scroll the webview offscreen
3. intersection observer still reports the webview as visible

What is the expected behavior?
Intersection observer should report the webview as not visible.

What went wrong?
In webviews, Intersection Observer will report that an element is fully visible even though the webview is off screen or scrolled out of view.  We propose that the calculations and event notifications of Intersection Observer should incorporate the visibility of the webview, not just the top-level document viewport.  This would enable ads in webviews to determine their visibility without any native-layer integration, and it would remove the messaging and polling-loop overhead of native-webview communication.

Did this work before? No 

Does this work in other browsers? N/A

Chrome version: 58.0.3029.110  Channel: stable
OS Version: 
Flash Version: