White page shown in custom tab when ublock blocks page

[pocmo]

From: mozilla-mobile/fenix#15095

When ublock is blocking the whole page in a custom page then only a white page is shown. In the browser itself a "This site was blocked ..." page is shown.

I can reproduce this fairly often by clicking on ads in gmail.

┆Issue is synchronized with this Jira Task

[csadilek]

Logs:

Error: File resource://default-theme/ does not contain a valid manifest 2 XPIInstall.jsm:669:11
Native manifests are not supported on android NativeManifests.jsm:53
    init resource://gre/modules/NativeManifests.jsm:53
    lookupManifest resource://gre/modules/NativeManifests.jsm:180
    lookupManagedStorage chrome://extensions/content/parent/ext-storage.js:45
    get chrome://extensions/content/parent/ext-storage.js:174
    get self-hosted:1176
    result resource://gre/modules/ExtensionParent.jsm:958
    withPendingBrowser resource://gre/modules/ExtensionParent.jsm:489
    result resource://gre/modules/ExtensionParent.jsm:958
    callAndLog resource://gre/modules/ExtensionParent.jsm:920
    recvAPICall resource://gre/modules/ExtensionParent.jsm:957
    AsyncFunctionNext self-hosted:689
null ExtensionCommon.jsm:742
    normalizeError resource://gre/modules/ExtensionCommon.jsm:742
    recvAPICall resource://gre/modules/ExtensionParent.jsm:973

[agi]

Reproducing this with a debugger attached I get a better stacktrace

normalizeError resource://gre/modules/ExtensionCommon.jsm:742
    recvAPICall resource://gre/modules/ExtensionParent.jsm:973
    (Async: promise callback)
    recvAPICall resource://gre/modules/ExtensionParent.jsm:964
    InterpretGeneratorResume self-hosted:1483
    AsyncFunctionNext self-hosted:689
    (Async: async)
    recvAPICall self-hosted:1176
    _recv resource://gre/modules/ConduitsChild.jsm:78
    receiveMessage resource://gre/modules/ConduitsParent.jsm:371
    (Async: JSActor query)
    _send resource://gre/modules/ConduitsChild.jsm:63
    _send resource://gre/modules/ConduitsChild.jsm:111
    _send self-hosted:1280
    callParentAsyncFunction resource://gre/modules/ExtensionChild.jsm:857
    callAsyncFunction resource://gre/modules/ExtensionChild.jsm:621
    stub resource://gre/modules/Schemas.jsm:2690
    update moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/vapi-background.js:542
    replace moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/vapi-background.js:561
    onBeforeRootFrameRequest moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/traffic.js:256
    onBeforeRequest moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/traffic.js:68
    onBeforeSuspendableRequest moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/vapi-background.js:1251
    onBeforeSuspendableRequest moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/vapi-webrequest.js:268
    <anonymous> moz-extension://3f5ff95f-5c98-42aa-9ff2-79bf737b91e2/js/vapi-background.js:1205
    apply self-hosted:2717
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.jsm:616
    fire resource://gre/modules/ExtensionChild.jsm:806
    recvRunListener resource://gre/modules/ExtensionChild.jsm:810
    recvRunListener self-hosted:1176
    _recv resource://gre/modules/ConduitsChild.jsm:78
    receiveMessage resource://gre/modules/ConduitsChild.jsm:184
    run resource://gre/modules/ConduitsChild.jsm:175
    receiveMessage resource://gre/modules/ConduitsChild.jsm:176
    map self-hosted:221
    receiveMessage resource://gre/modules/ConduitsChild.jsm:176
    (Async: JSActor query)
    send resource://gre/modules/ConduitsParent.jsm:336
    (Async: ChromeUtils::IdleDispatch handler)
    batch resource://gre/modules/ConduitsParent.jsm:339
    _send resource://gre/modules/ConduitsParent.jsm:226
    _send self-hosted:1280
    listener resource://gre/modules/ExtensionParent.jsm:1001
    apply self-hosted:2717
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.jsm:616
    applySafe resource://gre/modules/ExtensionParent.jsm:508
    sync resource://gre/modules/ExtensionCommon.jsm:2405
    listener chrome://extensions/content/parent/ext-webRequest.js:38
    runChannelListener resource://gre/modules/WebRequest.jsm:885
    forEach self-hosted:1949
    runChannelListener resource://gre/modules/WebRequest.jsm:826
    observe resource://gre/modules/WebRequest.jsm:658

[csadilek]

I think the problem here is that we don't register a TabDelegate for custom tabs, only for regular tabs.

[agi]

yeah the failure above is in tabs.update. I opened https://bugzilla.mozilla.org/show_bug.cgi?id=1682668 to improve the error messages.

[csadilek]

OK, confirmed that's the cause. Will put up a fix.