ozone/platform/wayland: Add support for wl_output_interface

ui/ozone/platform/wayland/wayland_screen.h

+// 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.
+
+#ifndef UI_OZONE_PLATFORM_WAYLAND_WAYLAND_SCREEN_H_
+#define UI_OZONE_PLATFORM_WAYLAND_WAYLAND_SCREEN_H_
+
+#include <stdint.h>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/ozone/platform/wayland/wayland_object.h"
+
+struct wl_output;

[rjkroege, 2016/06/14 23:29:49]

It would be nice if we didn't have to expose Wayland concepts at the top level
in an include file. Is there a reasonably easy way to do this? Perhaps add a
TODO to address this concern eventually.

[joone, 2016/06/20 22:22:42]

They are already forward-declared  in wayland_object.h so I will remove them
here.

+struct wl_registry;
+
+namespace ui {
+
+// WaylandScreen objects keep track of the current outputs (screens/monitors)

[rjkroege, 2016/06/14 23:29:49]

In chrome terminology, a Display corresponds to a single physical output CRT /
LCD etc while a Screen is the aggregate of all the attached Display(s). Despite
the extent to which this naming convention has confused me, please clarify the
comments here to make it clear if this is a Screen or a Display.

[Michael Forney, 2016/06/14 23:44:54]

I think this class corresponds to a wl_output which is a single physical output,
so Display is probably the proper term to use here.

Perhaps joone used Screen instead because WaylandDisplay was taken by the object
that refers to the wl_display object (which is the base object in a wayland
connection, like Display in Xlib or xcb_connection_t in xcb).

Here are some suggestions to resolve this:

- Rename WaylandDisplay -> WaylandConnection (or something like that), and this
class -> WaylandDisplay.
- Rename this class to WaylandOutput to match the wayland object it wraps.

[joone, 2016/06/20 22:22:42]

Thanks for suggestions. The name of the classes will be changed as follows:
Rename WaylandDisplay -> WaylandConnection 
Rename WaylandScreen -> WaylandOutput 

[Michael Forney, 2016/07/07 21:18:01]

Would you consider moving the rename of WaylandDisplay -> WaylandConnection to
its own CL?

[joone, 2016/07/12 19:22:41]

I've created a separate CL:
https://codereview.chromium.org/2147523003/

+// that are available to the application.
+class WaylandScreen {
+ public:
+  WaylandScreen(wl_registry* registry, uint32_t name, wl_output*);
+  ~WaylandScreen();
+
+  // Returns the active allocation of the screen.

[rjkroege, 2016/06/14 23:29:49]

These are are in DIP coordinates or DDP? Please indicate.

[joone, 2016/06/20 22:22:42]

This is the resolution of the screen.

+  gfx::Rect Geometry() const { return rect_; }
+
+  void OutputReadyForUse();
+  void WaitforOutputAvailable();
+
+ private:
+  // Callback functions that allows the display to initialize the screen's
+  // position and available modes.
+  static void OutputHandleGeometry(void* data,
+                                   wl_output* output,
+                                   int32_t x,
+                                   int32_t y,
+                                   int32_t physical_width,
+                                   int32_t physical_height,
+                                   int32_t subpixel,
+                                   const char* make,
+                                   const char* model,
+                                   int32_t output_transform);
+
+  static void OutputHandleMode(void* data,
+                               wl_output* wl_output,
+                               uint32_t flags,
+                               int32_t width,
+                               int32_t height,
+                               int32_t refresh);
+
+  wl::Object<wl_output> output_;
+  base::Closure output_complete_closure_;
+
+  int32_t name_;
+  gfx::Rect rect_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaylandScreen);
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PLATFORM_WAYLAND_WAYLAND_SCREEN_H_