Remove ALL usage of CriticalSectionWrapper.

webrtc/system_wrappers/source/rw_lock.cc

Index: webrtc/system_wrappers/source/rw_lock.cc
diff --git a/webrtc/system_wrappers/source/rw_lock.cc b/webrtc/system_wrappers/source/rw_lock.cc
index 7c77123a0b7eb79aa156174cd79b63322f823718..ff53e8d7a63dc3f4903a470f4e5f433f777a84dd 100644
--- a/webrtc/system_wrappers/source/rw_lock.cc
+++ b/webrtc/system_wrappers/source/rw_lock.cc
@@ -14,7 +14,6 @@
 
 #if defined(_WIN32)
 #include "webrtc/system_wrappers/source/rw_lock_win.h"
-#include "webrtc/system_wrappers/source/rw_lock_winxp_win.h"
 #else
 #include "webrtc/system_wrappers/source/rw_lock_posix.h"
 #endif
@@ -23,12 +22,7 @@ namespace webrtc {
 
 RWLockWrapper* RWLockWrapper::CreateRWLock() {
 #ifdef _WIN32
-  // Native implementation is faster, so use that if available.
-  RWLockWrapper* lock = RWLockWin::Create();
-  if (lock) {
-    return lock;
-  }
-  return new RWLockWinXP();
+  return RWLockWin::Create();
 #else
   return RWLockPosix::Create();
 #endif