Log Message:
firefox: Update to 81.0

Changelog:
September 22, 2020

Version 81.0, first offered to Release channel users on September 22, 2020

We'd like to extend a special thank you to all of the new Mozillians who
contributed to this release of Firefox.

New

  * You can pause and play audio or video in Firefox right from your keyboard
    or headset, giving you easy access to control your media when in another
    Firefox tab, another program, or even when your computer is locked.

  * In addition to our default, dark and light themes, with this release,
    Firefox introduces the Alpenglow theme: a colorful appearance for buttons,
    menus, and windows. You can update your Firefox themes under settings or
    preferences.

  * For our users in the US and Canada, Firefox can now save, manage, and
    auto-fill credit card information for you, making shopping on Firefox ever
    more convenient. To ensure the smoothest experience, this will be rolling
    out to users gradually.

  * Firefox supports AcroForm, which will soon allow you to fill in, print, and
    save supported PDF forms and the PDF viewer also has a new fresh look.

  * Our users in Austria, Belgium and Switzerland using the German version of
    Firefox will now see Pocket recommendations in their new tab featuring some
    of the best stories on the web. If you don’t see them, you can turn on
    Pocket articles in your new tab by following these steps. In addition to
    Firefox’s new tab, Pocket is also available as an app on iOS and Android.

Fixed

  * Various security fixes.

  * We’ve fixed a bug for users of language packs where the default language
    was reset to English after Firefox updates.

  * Browser native HTML5 audio/video controls received several important
    accessibility fixes:

      + Audio/video controls remain accessible to screen readers even when they
        are temporarily hidden visually.
      + Audio/video elapsed and total time are now accessible to screen readers
        where they weren't previously.
      + Various unlabelled controls are now labelled making them identifiable
        to screen readers.
      + Screen readers no longer intrusively report progress information unless
        the user requests it.

Changed

  * You will soon find Picture-in-Picture more easily on all the videos you
    watch with new iconography.

  * The bookmarks toolbar is now automatically revealed once bookmarks are
    imported into Firefox, making it easier to find your most important
    websites.

  * We have expanded our supported file types - .xml, .svg, and .webp - so
    files you’ve downloaded can be opened right in Firefox.

Security fixes:
#CVE-2020-15675: Use-After-Free in WebGL
#CVE-2020-15677: Download origin spoofing via redirect
#CVE-2020-15676: XSS when pasting attacker-controlled data into a
contenteditable element
#CVE-2020-15678: When recursing through layers while scrolling, an iterator may
have become invalid, resulting in a potential use-after-free scenario
#CVE-2020-15673: Memory safety bugs fixed in Firefox 81 and Firefox ESR 78.3
corruption and we presume that with enough effort some of these could have been
exploited to run arbitrary code.
#CVE-2020-15674: Memory safety bugs fixed in Firefox 81