services/ui: Set the gpu_channel_ to new added displays.

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 d02a6af4c018bca4d6e78382fe16ed279e5be03a..ad2862c300ae0c525953d812d3a1adbcd7f20c4c 100644
--- a/services/ui/ws/window_server.h
+++ b/services/ui/ws/window_server.h
@@ -220,7 +220,7 @@ class WindowServer : public ServerWindowDelegate,
   gfx::Rect GetCurrentMoveLoopRevertBounds();
   bool in_move_loop() const { return !!current_move_loop_; }
 
-  void OnFirstDisplayReady();
+  void OnDisplayReady(Display* display, bool is_first);
   void OnNoMoreDisplays();
   WindowManagerState* GetWindowManagerStateForUser(const UserId& user_id);
 
@@ -366,6 +366,7 @@ class WindowServer : public ServerWindowDelegate,
   uint32_t next_wm_change_id_;
 
   std::unique_ptr<GpuServiceProxy> gpu_proxy_;
+  scoped_refptr<gpu::GpuChannelHost> gpu_channel_;
   base::Callback<void(ServerWindow*)> window_paint_callback_;
 
   UserActivityMonitorMap activity_monitor_map_;