ui/window: Add platform windowing component

ui/window/platform_window_delegate.h

+// Copyright (c) 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.
+
+#ifndef UI_OZONE_PUBLIC_PLATFORM_WINDOW_DELEGATE_H_
+#define UI_OZONE_PUBLIC_PLATFORM_WINDOW_DELEGATE_H_
+
+#include "ui/events/platform/platform_event_dispatcher.h"
+#include "ui/window/window_export.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace ui {
+
+// Platform window delegate. See PlatformWindow.
+class WINDOW_EXPORT PlatformWindowDelegate
+    : public ui::PlatformEventDispatcher {

[sadrul, 2014/07/14 07:00:00]

This requires the PlatformWindowDelegate to keep processing platform-events
(i.e. XEvents etc.), which I think would be unfortunate. The way I am thinking
is the PlatformWindowDelegate should process only ui::Events instead (see
https://codereview.chromium.org/391583002/).

[spang, 2014/07/14 16:53:38]

That sounds good. In fact, this CL actually did that for ozone since  platform
event is currently defined as ui::Event.

+ public:
+  PlatformWindowDelegate() {}
+  virtual ~PlatformWindowDelegate() {}
+
+  // Notify the delegate that the window bounds have changed.
+  virtual void OnBoundsChanged(const gfx::Rect& new_bounds) = 0;
+
+  // Notify the delegate that the user has requested to close the window.
+  virtual void OnCloseRequest() = 0;

[Ben Goodger (Google), 2014/07/11 18:15:15]

If this really is a close request, this may need to provide the delegate a way
to abort the close.

Or do you want a destruction notification?

On Win32 the order is typically:

WM_CLOSE - user clicked the close button. The app can abort the close (e.g. if
there's unsaved work).
WM_DESTROY - the window is being closed. child windows are still valid.
WM_NCDESTROY - the window is being closed. child windows have been destroyed.

These states map in the various frameworks we have to the following states:
- Close
- Destroying
- Destroyed

FYI. :-)

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PlatformWindowDelegate);
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PUBLIC_PLATFORM_WINDOW_DELEGATE_H_