make debug mode ~20% faster on linux

base/threading/platform_thread_posix.cc

Index: base/threading/platform_thread_posix.cc
diff --git a/base/threading/platform_thread_posix.cc b/base/threading/platform_thread_posix.cc
index 5b609c1a9870ed4c397944a25bb08319711096b6..42b416d4a38fa1727d2e7043fd3ccd9a3e9e1a7e 100644
--- a/base/threading/platform_thread_posix.cc
+++ b/base/threading/platform_thread_posix.cc
@@ -164,7 +164,12 @@ PlatformThreadId PlatformThread::CurrentId() {
 #endif
 }
 
-//static
+// static
+PlatformThreadRef PlatformThread::CurrentRef() {
+  return PlatformThreadRef(pthread_self());
+}
+
+// static
 PlatformThreadHandle PlatformThread::CurrentHandle() {
   return PlatformThreadHandle(pthread_self(), CurrentId());
 }