Update from https://crrev.com/304121

base/threading/platform_thread_linux.cc

Index: base/threading/platform_thread_linux.cc
diff --git a/base/threading/platform_thread_linux.cc b/base/threading/platform_thread_linux.cc
index d9e2bd9932f5d107117eacd894d83334a9098d92..d97a3f4db5086171f28babda4e18d1f4303ff7ba 100644
--- a/base/threading/platform_thread_linux.cc
+++ b/base/threading/platform_thread_linux.cc
@@ -27,6 +27,7 @@ namespace base {
 
 namespace {
 
+#if !defined(OS_NACL)
 int ThreadNiceValue(ThreadPriority priority) {
   switch (priority) {
     case kThreadPriority_RealtimeAudio:
@@ -42,6 +43,7 @@ int ThreadNiceValue(ThreadPriority priority) {
       return 0;
   }
 }
+#endif  // !defined(OS_NACL)
 
 }  // namespace