ScreenWin Testability and Restructuring

ui/gfx/win/display_manager_observer.h

Index: ui/gfx/win/display_manager_observer.h
diff --git a/ui/gfx/win/display_manager_observer.h b/ui/gfx/win/display_manager_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..9e91c835a39c4dcf74687a8ea1e3f9c41fb5a489
--- /dev/null
+++ b/ui/gfx/win/display_manager_observer.h
@@ -0,0 +1,31 @@
+// 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_GFX_WIN_DISPLAY_MANAGER_CHANGE_OBSERVER_H_
+#define UI_GFX_WIN_DISPLAY_MANAGER_CHANGE_OBSERVER_H_
+
+#include <vector>
+
+#include "ui/gfx/gfx_export.h"
+
+namespace gfx {
+namespace win {
+
+class ScreenWinDisplay;
+
+class GFX_EXPORT DisplayManagerObserver {
+ public:
+  virtual void OnDisplaysChanged(
+      const std::vector<gfx::win::ScreenWinDisplay>& old_screen_win_displays,
+      const std::vector<gfx::win::ScreenWinDisplay>& new_screen_win_displays) =
+      0;
+
+ protected:
+  virtual ~DisplayManagerObserver() = default;
+};
+
+}  // namespace win
+}  // namespace gfx
+
+#endif  // UI_GFX_WIN_DISPLAY_MANAGER_OBSERVER_H_