+++ This bug was initially created as a clone of Bug #1634031 +++

This is

<panel id="pageActionPanel>

This is going to be a little tricky, but manageable.

I think steps that should roughly work are:

1. migrate to fluent for the labeling of actions. We probably need to accept that there will be "duplicate" labels for the tooltips used for actions in the address bar, and visible labels for the menuitems. This should get rid of the awkard inheritance of titles in takeActionTitleFromPanel from markup on the panel node itself.
2. update all supported actions that respond to other events (e.g. navigation) to check if the panel is present, without de-lazifying it, and otherwise only update in-addressbar nodes when this happens (if any).
3. change code in browser-pageActions.js to handle the panel not being present, and only actually create it if it is being shown.
4. doublecheck how this all works with extension-provided page actions...

Marking fxperf:p3 because I think it makes sense to start with the more straightforward cases.

https://hg.mozilla.org/mozilla-central/rev/b0c42fffcbc6

Backed out for failures on browser_menu_touch.js

backout: https://hg.mozilla.org/integration/autoland/rev/a58462ad649eb95372a1665480505bdefc2b7531

push: https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&revision=0798aa08c2cbe0f797ee107d516774ff6971b5eb&selectedTaskRun=Qf3dRX_AQrilDZGIHQhLIw.0

failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=317131520&repo=autoland&lineNumber=2354

also failing: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=317124861&repo=autoland&lineNumber=2437

Backed out changeset d4c1abcfbba0 (bug 1634042) for Browser-chrome failures in browser/base/content/test/touch/browser_menu_touch.js. CLOSED TREE

Log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=317327127&repo=autoland&lineNumber=14905

Push with failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&revision=d4c1abcfbba041e081049ae00e93e05f0e38a125

Backout:
https://hg.mozilla.org/integration/autoland/rev/e7a07501dc07f46d12642df102f2e58a0171c525

https://hg.mozilla.org/mozilla-central/rev/b95ecac8758c

🎉

Hey Emma, I'm seeing test failures in browser_UsageTelemetry_interaction.js and browser_UsageTelemetry_toolbars.js where the test tries to get access to #pageActionPanel but fails as the node is not created yet. I've replaced these locally with calls to BrowserPageActions.panelNode which forces the initialization. Are you aware of these failures? Should I include them in a separate commit for my work (it is unrelated and focused on the bookmarks toolbar)?

Thanks for pointing that out! Covering the test fixes in bug 1670269.