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

base/lazy_instance_unittest.cc

 // Copyright (c) 2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/at_exit.h"
 #include "base/atomic_sequence_num.h"
 #include "base/lazy_instance.h"
 #include "base/threading/simple_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 base::AtomicSequenceNumber constructed_seq_(base::LINKER_INITIALIZED);
 base::AtomicSequenceNumber destructed_seq_(base::LINKER_INITIALIZED);
 
 class ConstructAndDestructLogger {
  public:
   ConstructAndDestructLogger() {
     constructed_seq_.GetNext();
   }
   ~ConstructAndDestructLogger() {
     destructed_seq_.GetNext();
   }
 };
 
 class SlowConstructor {
  public:
   SlowConstructor() : some_int_(0) {
-    PlatformThread::Sleep(1000);  // Sleep for 1 second to try to cause a race.
+    // Sleep for 1 second to try to cause a race.
+    base::PlatformThread::Sleep(1000);
     ++constructed;
     some_int_ = 12;
   }
   int some_int() const { return some_int_; }
 
   static int constructed;
  private:
   int some_int_;
 };
 
@@ skipping 91 matching lines @@
   bool deleted2 = false;
   {
     base::ShadowingAtExitManager shadow;
     static base::LazyInstance<DeleteLogger,
                               base::LeakyLazyInstanceTraits<DeleteLogger> >
         test(base::LINKER_INITIALIZED);
     test.Get().SetDeletedPtr(&deleted2);
   }
   EXPECT_FALSE(deleted2);
 }