Implement the V2 sandbox in the process launcher.

content/public/common/content_features.cc

Index: content/public/common/content_features.cc
diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
index dee3ddee4a62de6c1bde601c987737c263cb2343..27be90f68d64eb4fb407dce508a1877d8a226076 100644
--- a/content/public/common/content_features.cc
+++ b/content/public/common/content_features.cc
@@ -391,4 +391,11 @@ const base::Feature kWinSboxDisableExtensionPoints{
     "WinSboxDisableExtensionPoint", base::FEATURE_ENABLED_BY_DEFAULT};
 #endif
 
+#if defined(OS_MACOSX)
+// The V2 sandbox on MacOS removes the unsandboed warmup phase and sandboxes the
+// entire life of the process.
+const base::Feature kMacV2Sandbox{"MacV2Sandbox",
+                                  base::FEATURE_DISABLED_BY_DEFAULT};
+#endif  // defined(OS_MACOSX)
+
 }  // namespace features