Masterbar: Proposal - Do not sign out by default from wpcom when clicking the Sign out link

[oskosk]

This is a proposal so it can be tested with the Jetpack Beta Plugin when the PR finishes being unit-tested by Travis.

Context: p1HpG7-4Fe-p2

Changes proposed in this Pull Request:

• Adds a filter jetpack_masterbar_should_logout_from_wpcom defaulting to false.
• Make the value be filtered to true for AT sites.

Testing instructions:

• Start by being signed in to WordPress.com (non-proxied).
• Then, on a connected Jetpack site...
• Install the Jetpack Beta Tester Plugin
• Select this PR ( Masterbar: Proposal - Do not sign out by default from wpcom when clicking the Sign out link #8243 ).
• Enable the Masterbar from the Jetpack Settings Page..
• Sign out from the Masterbar.
• Go back to WordPress.com.
• Expect to be logged in.

Repeat steps on an AT site but expect to be logged out from WordPress.com in the end.

• Start by being signed in to WordPress.com (non-proxied).
• Then, on an AT site...
• Install the Jetpack Beta Tester Plugin
• Select this PR ( Masterbar: Proposal - Do not sign out by default from wpcom when clicking the Sign out link #8243 ).
• Enable the Masterbar from the Jetpack Settings Page..
• Sign out from the Masterbar.
• Go back to WordPress.com.
• Expect to be logged out.

Changelog entry

We updated the sign out behaviour of the Masterbar to not sign you out of WordPress.com at the same time you sign out of your site.

[oskosk]

@vindl do you think this would work fine or if it would be desirable according to what was asked in #8173 (comment) ?

Also dropped p1HpG7-4Fe-p2 about this for discussion.

[vindl]

@vindl do you think this would work fine or if it would be desirable according to what was asked in #8173 (comment) ?

@oskosk I think this makes sense and codewise it looks good to me. 👍

[vindl]

/cc Atomic team just in case: @jhnstn @retrofox @donpark.

[oskosk]

@jhnstn @retrofox @donpark I'm merging this one.