[WIP] Make content_shell run under Wayland

ui/ozone/platform/wayland/desktop_platform_screen_delegate.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_DESKTOP_PLATFORM_SCREEN_DELEGATE_H_
+#define UI_OZONE_PLATFORM_WAYLAND_DESKTOP_PLATFORM_SCREEN_DELEGATE_H_
+
+namespace ui {
+
+// A simple observer interface for all clients interested in receiving various
+// output change notifications like size changes, when a new output is added,
+// etc.
+class DesktopPlatformScreenDelegate {
+ public:
+  // Called when the current output size has changed.
+  virtual void OnOutputSizeChanged(int32_t name,
+                                   unsigned width,
+                                   unsigned height) = 0;
+
+ protected:
+  virtual ~DesktopPlatformScreenDelegate() {}
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PLATFORM_WAYLAND_DESKTOP_PLATFORM_SCREEN_DELEGATE_H_