Disabling EME per configure option does not work on mobile anymore

While updating the mozconfig files for Android it turns out that ac_add_option --disable-eme does not work anymore.

We should investigate whether there is a suitable replacement and what the EME situation on Android is to make sure we still provide a DRM-free mobile experience.

Trac:
Parent Ticket: legacy/trac#30324 (moved)

added TorBrowserTeam201909R in Legacy / Trac component::applications/tor browser in Legacy / Trac ff68-esr in Legacy / Trac owner::tbb-team in Legacy / Trac parent::30324 in Legacy / Trac points::0.5 in Legacy / Trac priority::high in Legacy / Trac resolution::fixed in Legacy / Trac severity::normal in Legacy / Trac status::closed in Legacy / Trac tbb-9.0-must-alpha in Legacy / Trac tbb-rbm in Legacy / Trac type::defect in Legacy / Trac labels

Trac:
Points: N/A to 0.5

Configuring mobile/android/ with --disable-eme results in:

0:01.23 Traceback (most recent call last):
 0:01.23   File "/home/android/tor-browser/configure.py", line 132, in <module>
 0:01.23     sys.exit(main(sys.argv))
 0:01.23   File "/home/android/tor-browser/configure.py", line 38, in main
 0:01.23     sandbox.run(os.path.join(os.path.dirname(__file__), 'moz.configure'))
 0:01.23   File "/home/android/tor-browser/python/mozbuild/mozbuild/configure/__init__.py", line 441, in run
 0:01.23     self._value_for(option)
 0:01.23   File "/home/android/tor-browser/python/mozbuild/mozbuild/configure/__init__.py", line 528, in _value_for
 0:01.23     return self._value_for_option(obj)
 0:01.23   File "/home/android/tor-browser/python/mozbuild/mozbuild/util.py", line 947, in method_call
 0:01.23     cache[args] = self.func(instance, *args)
 0:01.23   File "/home/android/tor-browser/python/mozbuild/mozbuild/configure/__init__.py", line 591, in _value_for_option
 0:01.23     % option_string.split('=', 1)[0])
 0:01.23 mozbuild.configure.options.InvalidOptionError: --disable-eme is not available in this configuration
 0:01.27 *** Fix above errors and then restart with\
 0:01.27                "./mach build"
 0:01.27 client.mk:111: recipe for target 'configure' failed
 0:01.27 make: *** [configure] Error 1

--enable-eme only affects MOZ_EME_MODULES. The MODULES are only defined for browser. In FF67, enabling eme was restricted by OS, kernel, and CPU arch.

[https://searchfox.org/mozilla-esr68/source/toolkit/moz.configure#519 moz.configure}:

@depends(target)
def eme_choices(target):
    if (target.kernel in ('Darwin', 'WINNT', 'Linux') and
        target.os not in ('Android', 'iOS') and
        target.cpu in ('x86', 'x86_64')):
        return ('widevine',)
    if target.kernel == 'WINNT' and target.cpu == 'aarch64':
        return ('widevine',)
[snip]

option('--enable-eme',
       nargs='+',
       choices=eme_choices,
       default=eme_default,
       when=eme_choices,
       help='{Enable|Disable} support for Encrypted Media Extensions')

The "choices" returned by eme_choices is false-ish (I assume) on Android and iOS, and configure errors as a result of this.

        when = self._conditions.get(option)
        # If `when` resolves to a false-ish value, we always return None.
        # This makes option(..., when='--foo') equivalent to
        # option(..., when=depends('--foo')(lambda x: x)).
        if when and not self._value_for(when) and value is not None:
            # If the option was passed explicitly, we throw an error that
            # the option is not available. Except when the option was passed
            # from the environment, because that would be too cumbersome.
            if value.origin not in ('default', 'environment'):
                raise InvalidOptionError(
                    '%s is not available in this configuration'
                    % option_string.split('=', 1)[0])
            self._logger.log(TRACE, '%r = None', option)
            return None

Trac:
Status: new to needs_review
Keywords: TorBrowserTeam201909 deleted, TorBrowserTeam201909R added

Thanks. Looks good to me.

Trac:
Resolution: N/A to fixed
Status: needs_review to closed

For reference, see ticket:16285#comment:34

On Android, it's more interesting. #31880 didn't yield any interesting results
because nothing is changed at compile-time. Fennec and GeckoView use the Android
system DRM support when it is available. This is controlled separately by
media.mediadrm-widevinecdm.visible.

closed

changed time estimate to 4h

mentioned in issue legacy/trac#31881 (moved)

mentioned in issue legacy/trac#30324 (moved)

moved from legacy/trac#31880 (moved)

added Bug label and removed 1 deleted label

removed 1 deleted label

mentioned in issue #42501 (closed)

mentioned in issue mullvad-browser#282 (closed)