[views-mus] Prevent creating a native OzonePlatform in mus tests.

ui/aura/env.cc

Index: ui/aura/env.cc
diff --git a/ui/aura/env.cc b/ui/aura/env.cc
index 62475fd627e83a7bcc9ea7444cb3855ab45d4aba..7f9eba981cc7a00bcf5c17f8202dad5236c828cb 100644
--- a/ui/aura/env.cc
+++ b/ui/aura/env.cc
@@ -32,12 +32,6 @@ namespace {
 base::LazyInstance<base::ThreadLocalPointer<Env>>::Leaky lazy_tls_ptr =
     LAZY_INSTANCE_INITIALIZER;
 
-// Returns true if running inside of mus. Checks for mojo specific flag.
-bool RunningInsideMus() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      "primordial-pipe-token");
-}
-
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -151,7 +145,7 @@ Env::Env(Mode mode)
 }
 
 void Env::Init() {
-  if (RunningInsideMus()) {
+  if (mode_ == Mode::MUS) {
     EnableMusOSExchangeDataProvider();
     return;
   }