ozone/platform/wayland: Add support for wl_output_interface

ui/ozone/platform/wayland/wayland_output.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_OUTPUT_H_
+#define UI_OZONE_PLATFORM_WAYLAND_WAYLAND_OUTPUT_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"
+
+namespace ui {
+
+// WaylandOutput objects keep track of the current output of display
+// that are available to the application.
+class WaylandOutput {
+ public:
+  // Runs a callback when wl_output is available.
+  class Observer {
+   public:
+    explicit Observer(const base::Closure&, WaylandOutput*);
+    ~Observer();
+    // Will be called when wl_output is available.
+    void OnOutputReadyForUse();
+
+   private:
+    const base::Closure closure_;

[Michael Forney, 2016/07/20 21:49:00]

Why the closure? Why not just make OnOutputReadyForUse pure virtual?

What will use this interface?

[joone, 2016/07/20 23:23:59]

Observer is used in the test case in order to wait for the output messages from
Wayland Server.

+  };
+
+  WaylandOutput(wl_output*);
+  ~WaylandOutput();
+
+  // Returns the resolution of the screen.
+  gfx::Rect Geometry() const { return rect_; }
+  void SetObserver(Observer* observer) { observer_ = observer; }
+  Observer* observer() { return observer_; }
+
+ 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_;
+  gfx::Rect rect_;
+
+  Observer* observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaylandOutput);
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PLATFORM_WAYLAND_WAYLAND_SCREEN_H_