Made MessagePump a non-thread safe class.

chrome/browser/ui/cocoa/constrained_window/constrained_window_animation_unittest.mm

 // Copyright (c) 2012 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/mac/scoped_nsobject.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_pump_mac.h"
 #import "chrome/browser/ui/cocoa/cocoa_test_helper.h"
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_animation.h"
 
 // This class runs an animation for exactly two frames then end it.
 @interface ConstrainedWindowAnimationTestDelegate : NSObject
                                                    <NSAnimationDelegate> {
  @private
   CGFloat frameCount_;
-  scoped_refptr<base::MessagePumpNSRunLoop> message_pump_;
+  scoped_ptr<base::MessagePumpNSRunLoop> message_pump_;
 }
 
 - (void)runAnimation:(NSAnimation*)animation;
 
 @end
 
 @implementation ConstrainedWindowAnimationTestDelegate
 
 - (id)init {
   if ((self = [super init]))
-    message_pump_ = new base::MessagePumpNSRunLoop;
+    message_pump_.reset(new base::MessagePumpNSRunLoop);
   return self;
 }
 
 - (float)animation:(NSAnimation*)animation
     valueForProgress:(NSAnimationProgress)progress {
   ++frameCount_;
   if (frameCount_ >= 2)
     [animation setDuration:0.0];
   return frameCount_ == 1 ? 0.2 : 0.6;
 }
@@ skipping 36 matching lines @@
       [[ConstrainedWindowAnimationHide alloc] initWithWindow:test_window()]);
   [delegate_ runAnimation:animation];
 }
 
 // Test the pulse animation.
 TEST_F(ConstrainedWindowAnimationTest, Pulse) {
   base::scoped_nsobject<NSAnimation> animation(
       [[ConstrainedWindowAnimationPulse alloc] initWithWindow:test_window()]);
   [delegate_ runAnimation:animation];
 }