Bugzilla

### Beta/Release Uplift Approval Request
* **User impact if declined/Reason for urgency**: Loss of a safeguard in case the user removes the button and a malicious extension hides tabs.
* **Is this code covered by automated tests?**: Yes
* **Has the fix been verified in Nightly?**: No
* **Needs manual test from QE?**: Yes
* **If yes, steps to reproduce**: - Remove the all tabs button
- Install a tab hiding extension such as https://addons.mozilla.org/en-US/firefox/addon/hide-tabs-panic-button/
- Hide tabs via the extension
- Verify that the button is added back to the toolbar and hidden tabs are accessible from it
* **List of other uplifts needed**: None
* **Risk to taking this patch**: Medium
* **Why is the change risky/not risky? (and alternatives if risky)**: I want to acknowledge that this is not as tiny as part 1, but the code added here only runs when a webextension hides tabs, so it's fairly isolated.
* **String changes made/needed**: 
* **Is Android affected?**: No

### Beta/Release Uplift Approval Request
* **User impact if declined/Reason for urgency**: Loss of a safeguard in case the user removes the button and a malicious extension hides tabs.
* **Is this code covered by automated tests?**: Yes
* **Has the fix been verified in Nightly?**: No
* **Needs manual test from QE?**: Yes
* **If yes, steps to reproduce**: - Remove the all tabs button
- Install a tab hiding extension such as https://addons.mozilla.org/en-US/firefox/addon/panic-tabs/
- Hide tabs via the extension
- Verify that the button is added back to the toolbar and hidden tabs are accessible from it
* **List of other uplifts needed**: None
* **Risk to taking this patch**: Medium
* **Why is the change risky/not risky? (and alternatives if risky)**: I want to acknowledge that this is not as tiny as part 1, but the code added here only runs when a webextension hides tabs, so it's fairly isolated.
* **String changes made/needed**: 
* **Is Android affected?**: No