[WIP] Move ownership of PlatformDisplay from ws::Display to ws::WindowServer

services/ui/ws/window_server.h

Index: services/ui/ws/window_server.h
diff --git a/services/ui/ws/window_server.h b/services/ui/ws/window_server.h
index 17c15011997546cd246bbe77feb1388b817899ef..39d10b172dd45be33b2abd0649eab6fae0299fdd 100644
--- a/services/ui/ws/window_server.h
+++ b/services/ui/ws/window_server.h
@@ -35,6 +35,7 @@ class AccessPolicy;
 class Display;
 class DisplayManager;
 class GpuHost;
+class PlatformDisplay;
 class ServerWindow;
 class UserActivityMonitor;
 class WindowManagerState;
@@ -235,6 +236,9 @@ class WindowServer : public ServerWindowDelegate,
       const UserId& user_id,
       mojom::FrameDecorationValuesPtr* values) override;
 
+  void AddPlatformDisplay(std::unique_ptr<PlatformDisplay> platform_display);
+  void RemovePlatformDisplay(PlatformDisplay* platform_display);
+
  private:
   struct CurrentMoveLoopState;
   struct CurrentDragLoopState;
@@ -379,6 +383,8 @@ class WindowServer : public ServerWindowDelegate,
   // State for rendering into a Surface.
   cc::mojom::DisplayCompositorPtr display_compositor_;
 
+  std::set<std::unique_ptr<PlatformDisplay>> platform_displays_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowServer);
 };