CB-12875: (iOS) Pushes the inappbrowser window to a higher UI level then the existing…

[maltenorstroem]

… app's window

Platforms affected

iOS

What does this PR do?

Pushes the inappbrowser window to a higher UI leven then the existing app's window. Fix for CB-12875: (ios) Magnifiying glass is showing wrong content with inappbrowser window #251

What testing has been done on this change?

Tested on device (iOS 9.0, 10.2, 11.4) and simulator.

Checklist

• Reported an issue in the JIRA database
• Commit message follows the format: "CB-3232: (android) Fix bug with resolving file paths", where CB-xxxx is the JIRA ID & "android" is the platform affected.
• Added automated test coverage as appropriate for this change.

[janpio]

Are there any possible other side effects of this?
Behavior someone might rely on that changes?

[maltenorstroem]

In my opinion, this is a simple correction of the already created PR. The underlying window level is respected.

[shazron]

I see a failed build for MS Edge on Travis CI. I've tried multiple times restarting it, but it still fails. Looking at other PRs there seems to be general flakiness with browser builds.

Besides that, the PR LGTM

[janpio]

🥇 Thanks for your first merged PR @maltenorstroem! 💯