Use PostTask, not performSelector in NativeWidgetMac::Close()

ui/views/widget/native_widget_mac.mm

 // Copyright 2014 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 "ui/views/widget/native_widget_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include <utility>
 
+#import "base/mac/bind_objc_block.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/threading/thread_task_runner_handle.h"
 #import "ui/base/cocoa/constrained_window/constrained_window_animation.h"
 #import "ui/base/cocoa/window_size_constants.h"
 #include "ui/gfx/font_list.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #import "ui/gfx/mac/nswindow_frame_controls.h"
 #include "ui/native_theme/native_theme.h"
 #include "ui/native_theme/native_theme_mac.h"
 #import "ui/views/cocoa/bridged_content_view.h"
 #import "ui/views/cocoa/bridged_native_widget.h"
 #include "ui/views/cocoa/cocoa_mouse_capture.h"
@@ skipping 336 matching lines @@
 
   // Clear the view early to suppress repaints.
   bridge_->SetRootView(NULL);
 
   // Widget::Close() ensures [Non]ClientView::CanClose() returns true, so there
   // is no need to call the NSWindow or its delegate's -windowShouldClose:
   // implementation in the manner of -[NSWindow performClose:]. But,
   // like -performClose:, first remove the window from AppKit's display
   // list to avoid crashes like http://crbug.com/156101.
   [window orderOut:nil];
-  [window performSelector:@selector(close) withObject:nil afterDelay:0];
+
+  // Many tests assume that base::RunLoop().RunUntilIdle() is always sufficient
+  // to execute a close. However, in rare cases, -performSelector:..afterDelay:0
+  // does not do this. So post a regular task.
+  base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, base::BindBlock(^{
+    [window close];
+  }));
 }
 
 void NativeWidgetMac::CloseNow() {
   if (!bridge_)
     return;
 
   // Notify observers while |bridged_| is still valid.
   delegate_->OnNativeWidgetDestroying();
   // Reset |bridge_| to NULL before destroying it.
   std::unique_ptr<BridgedNativeWidget> bridge(std::move(bridge_));
@@ skipping 369 matching lines @@
   [[ViewsNSWindowCloseAnimator alloc] initWithWindow:window];
 }
 
 - (void)animationDidEnd:(NSAnimation*)animation {
   [window_ close];
   [animation_ setDelegate:nil];
   [self release];
 }
 
 @end