Listen to Display reconfiguration and notify DisplayObservers on Mac.

ui/gfx/screen_display_observer_delegate.h

Index: ui/gfx/screen_display_observer_delegate.h
diff --git a/ui/gfx/screen_display_observer_delegate.h b/ui/gfx/screen_display_observer_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..0fb912bcfcf9aac2ca6c250a195883bd1cce3612
--- /dev/null
+++ b/ui/gfx/screen_display_observer_delegate.h
@@ -0,0 +1,33 @@
+// 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.
+
+#ifndef UI_GFX_SCREEN_DISPLAY_OBSERVER_DELEGATE_H_
+#define UI_GFX_SCREEN_DISPLAY_OBSERVER_DELEGATE_H_
+
+#include <vector>
+
+#include "base/observer_list.h"
+#include "ui/gfx/display_observer.h"
+
+// ScreenDisplayObserverDelegate is a delegate for gfx::Screen. It helps
+// handling DisplayObserver's notification.
+class ScreenDisplayObserverDelegate {

[oshima, 2014/07/09 17:12:51]

DisplayChangeNotifier would be better name. The name "Delegate" in chromium is
used for a class that uses delegate pattern.

[mlamouri (slow - plz ping), 2014/07/10 12:54:34]

Done.

+ public:
+  ScreenDisplayObserverDelegate();
+  ~ScreenDisplayObserverDelegate();
+
+  void AddObserver(gfx::DisplayObserver* observer);
+
+  void RemoveObserver(gfx::DisplayObserver* observer);
+
+  void NotifyDisplaysChanged(const std::vector<gfx::Display>& old_displays,
+                             const std::vector<gfx::Display>& new_displays);
+
+ private:
+  // The observers that need to be notified when a display is modified, added
+  // or removed.
+  ObserverList<gfx::DisplayObserver> observer_list_;
+};

[oshima, 2014/07/09 17:12:51]

DISALLOW_COPY_AND_ASSIGN

[mlamouri (slow - plz ping), 2014/07/10 12:54:34]

Done.

+
+#endif // UI_GFX_SCREEN_DISPLAY_OBSERVER_DELEGATE_H_