Desktop aura: Expand what the ViewsDelegate can do to new windows.

ui/views/widget/widget.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_WIDGET_H_
 #define UI_VIEWS_WIDGET_WIDGET_H_
 
 #include <set>
 #include <stack>
 #include <vector>
@@ skipping 169 matching lines @@
     // specified, it's in screen's global coordinate system.
     gfx::Rect bounds;
     // When set, this value is used as the Widget's NativeWidget implementation.
     // The Widget will not construct a default one. Default is NULL.
     NativeWidget* native_widget;
     // Aura-only. Provides a DesktopRootWindowHost implementation to use instead
     // of the default one.
     // TODO(beng): Figure out if there's a better way to expose this, e.g. get
     // rid of NW subclasses and do this all via message handling.
     DesktopRootWindowHost* desktop_root_window_host;
+    // Whether this window is intended to be a toplevel window with no
+    // attachment to any other window.

[robertshield, 2012/12/14 01:15:58]

I initially found it confusing that a Widget can be top-level but may still have
a non-NULL |parent|. Could you mention that here?

     bool top_level;
     // Only used by NativeWidgetAura. Specifies the type of layer for the
     // aura::Window. Default is LAYER_TEXTURED.
     ui::LayerType layer_type;
     // Only used by Aura. Provides a context window whose RootWindow is
     // consulted during widget creation to determine where in the Window
     // hierarchy this widget should be placed. (This is separate from |parent|;
     // if you pass a RootWindow to |parent|, your window will be parented to
     // |parent|. If you pass a RootWindow to |context|, we ask that RootWindow
     // where it wants your window placed.) NULL is not allowed if you are using
@@ skipping 624 matching lines @@
 
   // Is |root_layers_| out of date?
   bool root_layers_dirty_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_H_