Bugzilla

Hey Luca, can you look into this error? One of my extensions is doing what basically amounts to this:
```
browser.windows.onFocusChanged.addListener(
  async (updateTabInfo) => await browser.tabs.getCurrent()
);
```
And the extension is working perfectly fine but it's logging errors when I focus a window:
```
NS_ERROR_XPC_SECURITY_MANAGER_VETO: ExtensionChild.jsm:629
    callAsyncFunction resource://gre/modules/ExtensionChild.jsm:629
    stub resource://gre/modules/Schemas.jsm:2847
    loadLatestData moz-extension://e158f52d-b5db-4594-9757-1e526a5df811/newtab.js:187
    apply self-hosted:2719
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.jsm:693
    fire resource://gre/modules/ExtensionChild.jsm:838
    recvRunListener resource://gre/modules/ExtensionChild.jsm:842
    recvRunListener self-hosted:1165
    _recv resource://gre/modules/ConduitsChild.jsm:82
    receiveMessage resource://gre/modules/ConduitsChild.jsm:188
    (Async: JSActor query)
    _send resource://gre/modules/ConduitsChild.jsm:65
    _send resource://gre/modules/ConduitsParent.jsm:290
    _send self-hosted:1269
    listener resource://gre/modules/ExtensionParent.jsm:1081
    apply self-hosted:2719
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.jsm:693
    applySafe resource://gre/modules/ExtensionParent.jsm:553
    async resource://gre/modules/ExtensionCommon.jsm:2577
    (Async: promise callback)
    async resource://gre/modules/ExtensionCommon.jsm:2574
    listener chrome://browser/content/parent/ext-windows.js:66
    (Async: promise callback)
    listener chrome://browser/content/parent/ext-windows.js:59
    (Async: EventListener.handleEvent)
    _addWindowListener chrome://extensions/content/parent/ext-tabs-base.js:1853
    addListener chrome://extensions/content/parent/ext-tabs-base.js:1788
    onFocusChanged chrome://browser/content/parent/ext-windows.js:72
    onFocusChanged self-hosted:1165
    registerEventListener resource://gre/modules/ExtensionCommon.jsm:413
    register resource://gre/modules/ExtensionCommon.jsm:2253
    addListener resource://gre/modules/ExtensionCommon.jsm:2653
    addListener resource://gre/modules/ExtensionCommon.jsm:2717
    recvAddListener resource://gre/modules/ExtensionParent.jsm:1127
    InterpretGeneratorResume self-hosted:1472
    AsyncFunctionNext self-hosted:682
    (Async: async)
    recvAddListener self-hosted:1165
    _recv resource://gre/modules/ConduitsChild.jsm:82
    receiveMessage resource://gre/modules/ConduitsParent.jsm:450
```
which I guess the exception is sanitized and reported further downstream:
```
InvalidStateError: An exception was thrown newtab.js:187
```
Anyway, that ExtensionChild.jsm:629 is this line:
```
    const isHandlingUserInput =
      context.contentWindow?.windowUtils?.isHandlingUserInput;
```
Such a strange coincidence that I would just happen to notice this myself haha

Hey Luca, can you look into this error? One of my extensions is doing what basically amounts to this:
```
browser.windows.onFocusChanged.addListener(
  async (updateTabInfo) => await browser.tabs.getCurrent()
);
```
And the extension is working perfectly fine but it's logging errors when I focus a window:
```
NS_ERROR_XPC_SECURITY_MANAGER_VETO: ExtensionChild.jsm:629
    callAsyncFunction resource://gre/modules/ExtensionChild.jsm:629
    stub resource://gre/modules/Schemas.jsm:2847
    loadLatestData moz-extension://e158f52d-b5db-4594-9757-1e526a5df811/newtab.js:187
    apply self-hosted:2719
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.jsm:693
    fire resource://gre/modules/ExtensionChild.jsm:838
    recvRunListener resource://gre/modules/ExtensionChild.jsm:842
    recvRunListener self-hosted:1165
    _recv resource://gre/modules/ConduitsChild.jsm:82
    receiveMessage resource://gre/modules/ConduitsChild.jsm:188
    (Async: JSActor query)
    _send resource://gre/modules/ConduitsChild.jsm:65
    _send resource://gre/modules/ConduitsParent.jsm:290
    _send self-hosted:1269
    listener resource://gre/modules/ExtensionParent.jsm:1081
    apply self-hosted:2719
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.jsm:693
    applySafe resource://gre/modules/ExtensionParent.jsm:553
    async resource://gre/modules/ExtensionCommon.jsm:2577
    (Async: promise callback)
    async resource://gre/modules/ExtensionCommon.jsm:2574
    listener chrome://browser/content/parent/ext-windows.js:66
    (Async: promise callback)
    listener chrome://browser/content/parent/ext-windows.js:59
    (Async: EventListener.handleEvent)
    _addWindowListener chrome://extensions/content/parent/ext-tabs-base.js:1853
    addListener chrome://extensions/content/parent/ext-tabs-base.js:1788
    onFocusChanged chrome://browser/content/parent/ext-windows.js:72
    onFocusChanged self-hosted:1165
    registerEventListener resource://gre/modules/ExtensionCommon.jsm:413
    register resource://gre/modules/ExtensionCommon.jsm:2253
    addListener resource://gre/modules/ExtensionCommon.jsm:2653
    addListener resource://gre/modules/ExtensionCommon.jsm:2717
    recvAddListener resource://gre/modules/ExtensionParent.jsm:1127
    InterpretGeneratorResume self-hosted:1472
    AsyncFunctionNext self-hosted:682
    (Async: async)
    recvAddListener self-hosted:1165
    _recv resource://gre/modules/ConduitsChild.jsm:82
    receiveMessage resource://gre/modules/ConduitsParent.jsm:450
```
which I guess the exception is sanitized and reported further downstream:
```
InvalidStateError: An exception was thrown newtab.js:187
```
Anyway, that ExtensionChild.jsm:629 is this line:
```
    const isHandlingUserInput =
      context.contentWindow?.windowUtils?.isHandlingUserInput;
```
Such a strange coincidence that I would just happen to notice this myself haha.

[Here's the addon](https://github.com/wildskyf/tab-notes) if that helps.