Use the suid helper for oom_score_adj on Chrome OS.

content/browser/zygote_host/zygote_communication_linux.cc

Index: content/browser/zygote_host/zygote_communication_linux.cc
diff --git a/content/browser/zygote_host/zygote_communication_linux.cc b/content/browser/zygote_host/zygote_communication_linux.cc
index b2aa341ac0e3664a7f8d78cc06f31d0faf515fa6..0a53da96e8a7517361d802a650118b06a9ae4c52 100644
--- a/content/browser/zygote_host/zygote_communication_linux.cc
+++ b/content/browser/zygote_host/zygote_communication_linux.cc
@@ -303,9 +303,16 @@ void ZygoteCommunication::Init() {
   // Use the SUID sandbox for adjusting OOM scores when we are using the setuid
   // or namespace sandbox. This is needed beacuse the processes are
   // non-dumpable, so /proc/pid/oom_score_adj can only be written by root.
-  use_suid_sandbox_for_adj_oom_score_ =
-      !ZygoteHostImpl::GetInstance()->SandboxCommand().empty() &&
-      using_suid_sandbox;
+  use_suid_sandbox_for_adj_oom_score_ = using_suid_sandbox;
+
+#if defined(OS_CHROMEOS)
+  // Chrome OS has a kernel patch that restricts oom_score_adj. See
+  // crbug.com/576409 for details.
+  if (!ZygoteHostImpl::GetInstance()->SandboxCommand().empty() &&
+      using_namespace_sandbox) {
+    use_suid_sandbox_for_adj_oom_score_ = true;
+  }
+#endif
 
   // Start up the sandbox host process and get the file descriptor for the
   // renderers to talk to it.