MacViews: Attach child windows when parent is on the screen.

ui/views/cocoa/bridged_native_widget.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/cocoa/bridged_native_widget.h"
 
 #import <objc/runtime.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 766 matching lines @@
   // BridgedContentView.
   if (base::mac::IsOSMavericks() && ![window_ inLiveResize])
     [bridged_view_ updateWindowMask];
 }
 
 void BridgedNativeWidget::OnPositionChanged() {
   native_widget_mac_->GetWidget()->OnNativeWidgetMove();
 }
 
 void BridgedNativeWidget::OnVisibilityChanged() {
-  OnVisibilityChangedTo([window_ isVisible]);
-}
-
-void BridgedNativeWidget::OnVisibilityChangedTo(bool new_visibility) {
-  if (window_visible_ == new_visibility)
+  const bool window_visible = [window_ isVisible];
+  if (window_visible_ == window_visible)
     return;
 
-  window_visible_ = new_visibility;
+  window_visible_ = window_visible;
 
   // If arriving via SetVisible(), |wants_to_be_visible_| should already be set.
   // If made visible externally (e.g. Cmd+H), just roll with it. Don't try (yet)
   // to distinguish being *hidden* externally from being hidden by a parent
   // window - we might not need that.
   if (window_visible_) {
     wants_to_be_visible_ = true;
 
     if (parent_)
       [parent_->GetNSWindow() addChildWindow:window_ ordered:NSWindowAbove];
@@ skipping 552 matching lines @@
   [bridged_view_ setMouseDownCanMoveWindow:draggable];
   // AppKit will not update its cache of mouseDownCanMoveWindow unless something
   // changes. Previously we tried adding an NSView and removing it, but for some
   // reason it required reposting the mouse-down event, and didn't always work.
   // Calling the below seems to be an effective solution.
   [window_ setMovableByWindowBackground:NO];
   [window_ setMovableByWindowBackground:YES];
 }
 
 }  // namespace views