Changes views_aura_mus_unittests to create DesktopNativeWidgetAura

ui/views/test/platform_test_helper.mm

+// Copyright 2016 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/test/platform_test_helper.h"
+
+#include <Cocoa/Cocoa.h>
+
+#import "base/mac/scoped_nsobject.h"
+#import "base/mac/scoped_objc_class_swizzler.h"
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#import "ui/views/cocoa/bridged_native_widget.h"
+#include "ui/views/widget/native_widget_mac.h"
+#include "ui/views/widget/widget.h"
+
+namespace views {
+namespace {
+
+class DefaultPlatformTestHelper : public PlatformTestHelper {
+ public:
+  DefaultPlatformTestHelper() {}
+  ~DefaultPlatformTestHelper() override {}
+
+  // PlatformTestHelper:
+  void SimulateNativeDestroy(Widget* widget) override {
+    // Retain the window while closing it, otherwise the window may lose its
+    // last

[msw, 2016/11/11 00:29:25]

nit: wrapping

[sky, 2016/11/11 01:09:14]

Done.

+    // owner before -[NSWindow close] completes (this offends AppKit). Usually
+    // this reference will exist on an event delivered to the runloop.
+    base::scoped_nsobject<NSWindow> window([widget->GetNativeWindow() retain]);
+    [window close];
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DefaultPlatformTestHelper);
+};
+
+}  // namespace
+
+// static
+std::unique_ptr<PlatformTestHelper> PlatformTestHelper::Create() {
+  return base::WrapUnique(new DefaultPlatformTestHelper);
+}
+
+}  // namespace views