Make --headless flag work on Mac

chrome/app/chrome_main.cc

Index: chrome/app/chrome_main.cc
diff --git a/chrome/app/chrome_main.cc b/chrome/app/chrome_main.cc
index 2210192aa71c441f096499c9c2a25b462bc92c17..0d7a8ad573e4f220d0fff90b8afe7255dba4b18f 100644
--- a/chrome/app/chrome_main.cc
+++ b/chrome/app/chrome_main.cc
@@ -22,6 +22,10 @@
 #include "services/service_manager/runner/common/client_util.h"
 #endif
 
+#if defined(OS_MACOSX)
+#include "chrome/app/chrome_main_mac.h"
+#endif
+
 #if defined(OS_WIN)
 #include "base/debug/dump_without_crashing.h"
 #include "base/win/win_util.h"
@@ -93,10 +97,14 @@ int ChromeMain(int argc, const char** argv) {
   ALLOW_UNUSED_LOCAL(command_line);
 #endif
 
-#if defined(OS_LINUX)
-  if (command_line->HasSwitch(switches::kHeadless))
+#if defined(OS_LINUX) || defined(OS_MACOSX)
+  if (command_line->HasSwitch(switches::kHeadless)) {
+#if defined(OS_MACOSX)
+    SetUpBundleOverrides();
+#endif
     return headless::HeadlessShellMain(argc, argv);
-#endif  // defined(OS_LINUX)
+  }
+#endif  // defined(OS_LINUX) || defined(OS_MACOSX)
 
 #if BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
   version_info::Channel channel = chrome::GetChannel();