Attempt four at landing the "histogram.h removed from message_loop.h" patch.

base/weak_ptr_unittest.cc

 // Copyright (c) 2010 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 "testing/gtest/include/gtest/gtest.h"
 #include "base/message_loop.h"
 #include "base/thread.h"
+#include "base/scoped_ptr.h"
 #include "base/weak_ptr.h"
 
 namespace base {
 namespace {
 
 template <class T>
 class OffThreadObjectCreator {
  public:
   static T* NewObject() {
     T* result;
@@ skipping 109 matching lines @@
   // Test that it is OK to create a class that has a WeakPtr member on one
   // thread, but use it on another.  This tests that we do not trip runtime
   // checks that ensure that a weak reference is not used by multiple threads.
   scoped_ptr<Consumer> consumer(OffThreadObjectCreator<Consumer>::NewObject());
   Producer producer;
   consumer->producer = producer.AsWeakPtr();
   EXPECT_EQ(&producer, consumer->producer.get());
 }
 
 }  // namespace base