MacViews: Implement CloseNow() as just -[NSWindow close].

ui/views/widget/native_widget_mac_unittest.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.
 
 #import "ui/views/widget/native_widget_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #import "base/mac/foundation_util.h"
 #import "base/mac/scoped_nsautorelease_pool.h"
@@ skipping 1136 matching lines @@
     parent_nswindow_.reset([[child->GetNativeWindow() parentWindow] retain]);
     EXPECT_TRUE(parent_nswindow_);
     EXPECT_TRUE([parent_nswindow_ delegate]);
   }
 
   ~ParentCloseMonitor() override {
     EXPECT_TRUE(child_closed_);  // Otherwise the observer wasn't removed.
   }
 
   void OnWidgetDestroying(Widget* child) override {
-    // Upon a parent-triggered close, the NSWindow relationship will already be
-    // removed. The parent should still be open (children are always closed
-    // first), but not have a delegate (since it is being torn down).
+    // Upon a parent-triggered close, the NSWindow relationship will still exist
+    // (it's removed just after OnWidgetDestroying() returns). The parent should
+    // still be open (children are always closed first), but not have a delegate
+    // (since it is being torn down).
+    EXPECT_TRUE([child->GetNativeWindow() parentWindow]);
+    EXPECT_TRUE([parent_nswindow_ isVisible]);
+    EXPECT_FALSE([parent_nswindow_ delegate]);
+
+    EXPECT_FALSE(child_closed_);
+  }
+
+  void OnWidgetDestroyed(Widget* child) override {
     EXPECT_FALSE([child->GetNativeWindow() parentWindow]);
     EXPECT_TRUE([parent_nswindow_ isVisible]);
     EXPECT_FALSE([parent_nswindow_ delegate]);
 
     EXPECT_FALSE(child_closed_);
     child->RemoveObserver(this);
     child_closed_ = true;
   }
 
   bool child_closed() const { return child_closed_; }
@@ skipping 623 matching lines @@
 
 - (void)dealloc {
   if (deallocFlag_) {
     DCHECK(!*deallocFlag_);
     *deallocFlag_ = true;
   }
   [super dealloc];
 }
 
 @end