Pace humanized moves on their own schedule, and write toggle prefs on every launch (#808)

* fix(juggler): pace a humanized move on its own schedule

sendTrajectoryAcked waited each point's full pause after the previous
point's ack, so every ack's round trip was added to the move: it took
its plan plus one round trip per point. On a page whose main thread is
busy 19ms in every 20, moves capped at 0.5s took 0.54-0.71s. Each point
is now due at its planned offset from the start of the move, so a late
ack delays only its own point and the move ends on its planned time.

tests/patches/humanize-pacing.py times eleven capped moves on such a
page and checks their median against the cap. It failed 3/3 before
(medians 587-607ms) and passes after (484-487ms).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

* fix(launch): write toggle prefs on every launch, on or off

block_webrtc, block_images and disable_coop wrote their pref only when
switched on. A persistent profile keeps a user.js pref in prefs.js, so
removing the flag later left the setting in force. A real profile
launched once with block_webrtc still had media.peerconnection.enabled
false long after, and BrowserScan reported WebRTC disabled.

Each pref is now written every launch, with the stock value when its
flag is off. A caller's own firefox_user_prefs entry still wins. The
same change is made in the TypeScript launcher, with its tests.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pythonlib/camoufox/utils.py

@@ -1429,15 +1429,16 @@ def launch_options(
     if allow_addon_new_tab:
         set_into(config, 'allowAddonNewtab', True)
 
-    # Set Firefox user preferences
+    # Set Firefox user preferences. Each toggle writes its pref on or off: a
+    # persistent profile keeps a user.js pref in prefs.js after the launch that
+    # set it, so a flag that only wrote when on stayed on for good.
     if block_images:
         LeakWarning.warn('block_images', i_know_what_im_doing)
-        firefox_user_prefs['permissions.default.image'] = 2
-    if block_webrtc:
-        firefox_user_prefs['media.peerconnection.enabled'] = False
     if disable_coop:
         LeakWarning.warn('disable_coop', i_know_what_im_doing)
-        firefox_user_prefs['browser.tabs.remote.useCrossOriginOpenerPolicy'] = False
+    firefox_user_prefs.setdefault('permissions.default.image', 2 if block_images else 1)
+    firefox_user_prefs.setdefault('media.peerconnection.enabled', not block_webrtc)
+    firefox_user_prefs.setdefault('browser.tabs.remote.useCrossOriginOpenerPolicy', not disable_coop)
     # A persistent context takes its context options here.
     if launch_options.get('is_mobile'):
         LeakWarning.warn('is_mobile', i_know_what_im_doing)

pythonlib/tests/test_launch_environment.py

@@ -171,6 +171,41 @@ class TestUiLocaleFollowsIntlLocale:
         assert prefs[self.PREF] == "de"
 
 
+class TestToggleSettingsAreWrittenBothWays:
+    """A persistent profile keeps every pref it was ever launched with.
+
+    Firefox saves a user.js pref into prefs.js, and a later launch that simply
+    omits it does not clear it. A profile once launched with block_webrtc kept
+    WebRTC off after the flag was removed (a real profile's prefs.js still held
+    media.peerconnection.enabled=false), so each toggle writes its pref on every
+    launch, on or off.
+    """
+
+    UA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:152.0) Gecko/20100101 Firefox/152.0"
+    TOGGLES = [
+        ("block_webrtc", "media.peerconnection.enabled", True, False),
+        ("block_images", "permissions.default.image", 1, 2),
+        ("disable_coop", "browser.tabs.remote.useCrossOriginOpenerPolicy", True, False),
+    ]
+
+    def _prefs(self, **kwargs):
+        return utils.launch_options(
+            config={"navigator.userAgent": self.UA}, i_know_what_im_doing=True, **kwargs
+        )["firefox_user_prefs"]
+
+    @pytest.mark.parametrize("flag, pref, stock, toggled", TOGGLES)
+    def test_off_writes_the_stock_value(self, isolated_launch_dependencies, flag, pref, stock, toggled):
+        assert self._prefs()[pref] == stock
+
+    @pytest.mark.parametrize("flag, pref, stock, toggled", TOGGLES)
+    def test_on_writes_the_toggled_value(self, isolated_launch_dependencies, flag, pref, stock, toggled):
+        assert self._prefs(**{flag: True})[pref] == toggled
+
+    @pytest.mark.parametrize("flag, pref, stock, toggled", TOGGLES)
+    def test_caller_pref_wins(self, isolated_launch_dependencies, flag, pref, stock, toggled):
+        assert self._prefs(firefox_user_prefs={pref: toggled})[pref] == toggled
+
+
 class TestPrefsReachStartup:
     """Launcher prefs must be readable by camoufox.cfg at startup.