792891 - Add way to detect from parent process whether a TabParent is visible, and use that for backstop permissions checks

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: General, defect)

Description

[Justin Lebar (not reading bugmail)]

In bug 791261, we removed a backstop capability check in the parent process, which we would like to add back.

The issue is that pages should not be able to call navigator.vibrate if they're not visible.  We do a check for this in the child process, but we should also do a check in the parent process that the vibrating process has at least one visible window.

We tried to this check in using TabParent::Active(), but it turns out that was set by the focus manager, and that doesn't quite correspond to what we want -- only one TabParent can be focused at a time, but more than one TabParent can have vibration permissions at the same time.

BrowserElementParent knows whether an OOP frame is visible.  So a solution to this bug is to somehow communicate that information to the BEP's TabParent.  We can then use that information to do our backstop check in the parent.

Comment 1

[BMO Automation]

Firefox OS is not being worked on