Move platform_thread to base/threading and put in the base namespace. I left ...

base/threading/thread_checker.cc

Index: base/threading/thread_checker.cc
===================================================================
--- base/threading/thread_checker.cc	(revision 70321)
+++ base/threading/thread_checker.cc	(working copy)
@@ -2,11 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/thread_checker.h"
+#include "base/threading/thread_checker.h"
 
 // This code is only done in debug builds.
 #ifndef NDEBUG
 
+namespace base {
+
 ThreadChecker::ThreadChecker() : valid_thread_id_(kInvalidThreadId) {
   EnsureThreadIdAssigned();
 }
@@ -31,4 +33,6 @@
   valid_thread_id_ = PlatformThread::CurrentId();
 }
 
+}  // namespace base
+
 #endif  // NDEBUG