Fix to allow single-process on Linux. (#4290)

This adds a fix to allow cobalt to be ran in a single_process on Linux,
and
adds the flag to the poor-man's cobalt wrapper.

b/375192642
b/374191454

base/BUILD.gn

@@ -2477,7 +2477,7 @@ buildflag_header("debugging_buildflags") {
 
   # TODO(crbug.com/1420774): Try and enable these checks on Android too.
   enable_commandline_sequence_checks =
-      (is_debug || dcheck_always_on) && !is_android
+      (is_debug || dcheck_always_on) && !is_android && !is_cobalt
 
   flags = [
     "DCHECK_IS_CONFIGURABLE=$dcheck_is_configurable",

cobalt/cobalt.cc

@@ -39,15 +39,15 @@ int main(int argc, const char** argv) {
   // parameters, also update the my_argc below.
   static const char* my_argv[] = {
       argv[0], "--disable-fre", "--no-first-run", "--kiosk",
-      "--force-video-overlays",
+      "--force-video-overlays", "--single-process",
       // Enable remote devtools access.
       "--remote-debugging-port=9222",
       "--remote-allow-origins=http://localhost:9222",
       // This flag is added specifically for m114 and should be removed after
       // rebasing to m120+
       "--user-level-memory-pressure-signal-params",
       "https://www.youtube.com/tv", nullptr, nullptr};
-  int my_argc = 9;
+  int my_argc = 10;
 
   // TODO: (cobalt b/375241103) Reimplement this in a clean way.
   // This expression exists to ensure that we apply the argument overrides