refactor(linux): drop child-process switch stripping (fixed upstream in CEF 147)

BrowserProcessHandler_OnBeforeChildProcessLaunch stripped
--pseudonymization-salt-handle and --change-stack-guard-on-fork from every
child command line to avoid CEF 146 subprocess crashes ("Failed global
descriptor lookup: 7" on non-zygote utilities; "stack smashing detected" on
zygote-forked children).

Re-verified on CEF 147: both switches are still added by Chrome to child
command lines, but their presence no longer crashes the subprocesses. Tested
with the strip disabled across every relevant path — sandbox on (zygote),
the unit-test no-zygote/in-process config, and the exact target scenario
(--no-zygote with a directly-launched utility subprocess carrying
--pseudonymization-salt-handle): no descriptor-lookup failure, no stack-smash,
hello_world and the 85 unit tests all pass. Upstream evidently fixed the
non-zygote GlobalDescriptors init and the fork-canary handling between 146
and 147.

Removes the Linux-only CefCommandLine rewriting from the .pyx binding layer.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: linesight

src/handlers/browser_process_handler.pyx

@@ -27,76 +27,6 @@ cdef public void BrowserProcessHandler_OnBeforeChildProcessLaunch(
         ) noexcept with gil:
     try:
         AppendSwitchesToCommandLine(cefCommandLine, g_commandLineSwitches)
-        IF UNAME_SYSNAME == "Linux":
-            _StripPseudonymizationSaltHandle(cefCommandLine)  # strips crash-inducing switches
     except:
         (exc_type, exc_value, exc_trace) = sys.exc_info()
         sys.excepthook(exc_type, exc_value, exc_trace)
-
-
-IF UNAME_SYSNAME == "Linux":
-    # Switches that must be stripped from every child-process command line on
-    # Linux to prevent crashes in CEF 146 subprocesses.
-    #
-    # --pseudonymization-salt-handle (Chrome 130+):
-    #   Passed to directly-launched (non-zygote) utility subprocesses,
-    #   expecting GlobalDescriptors[key=7] to already be populated.
-    #   CEF 146 does not perform this GlobalDescriptors initialization for
-    #   the non-zygote path, so the subprocess crashes:
-    #     "Failed global descriptor lookup: 7"
-    #   Removing the switch causes Chrome to use a per-process random salt.
-    #
-    # --change-stack-guard-on-fork (Chrome / Linux zygote):
-    #   Tells a Zygote-forked child to randomize its stack canary after fork.
-    #   ChangeStackGuard() is called from inside the Zygote event-loop stack
-    #   frames that the fork() inherited.  Those frames have the pre-fork
-    #   canary saved; when they return the canary check fails:
-    #     "*** stack smashing detected ***: terminated"
-    #   The subprocess exits before Chrome's initialization completes, so
-    #   OnContextInitialized never fires.  Removing the switch prevents
-    #   ChangeStackGuard() from being called at all; the child keeps the
-    #   Zygote's canary (which is still randomized at Zygote startup).
-    _STRIP_CHILD_SWITCHES = frozenset([
-        "pseudonymization-salt-handle",
-        "change-stack-guard-on-fork",
-    ])
-
-    cdef void _StripPseudonymizationSaltHandle(
-            CefRefPtr[CefCommandLine] cefCommandLine) except * with gil:
-        cdef CefString cefSwitchName
-        cdef bint needs_strip = False
-        for sw in _STRIP_CHILD_SWITCHES:
-            cefSwitchName = PyToCefStringValue(sw)
-            if cefCommandLine.get().HasSwitch(cefSwitchName):
-                needs_strip = True
-                break
-        if not needs_strip:
-            return
-
-        # Capture current state before resetting.
-        cdef CefString program
-        program = cefCommandLine.get().GetProgram()
-
-        cdef cpp_map[CefString, CefString] switches
-        cefCommandLine.get().GetSwitches(switches)
-
-        cdef cpp_vector[CefString] arguments
-        cefCommandLine.get().GetArguments(arguments)
-
-        # Rebuild command line omitting the problem switches.
-        cefCommandLine.get().Reset()
-        cefCommandLine.get().SetProgram(program)
-
-        cdef cpp_map[CefString, CefString].iterator it = switches.begin()
-        while it != switches.end():
-            if CefToPyString(deref(it).first) not in _STRIP_CHILD_SWITCHES:
-                if deref(it).second.empty():
-                    cefCommandLine.get().AppendSwitch(deref(it).first)
-                else:
-                    cefCommandLine.get().AppendSwitchWithValue(
-                        deref(it).first, deref(it).second)
-            preinc(it)
-
-        cdef size_t i
-        for i in range(arguments.size()):
-            cefCommandLine.get().AppendArgument(arguments[i])