chromeos: changes how DisplayManagerObservers are notified

ui/aura/test/mus/test_window_manager_client.h

Index: ui/aura/test/mus/test_window_manager_client.h
diff --git a/ui/aura/test/mus/test_window_manager_client.h b/ui/aura/test/mus/test_window_manager_client.h
index 468f6d10586f0c33285af19716c50ee2a0b70d45..87373d231c44f2a7db14e2e4ad43aed0f3b46c1d 100644
--- a/ui/aura/test/mus/test_window_manager_client.h
+++ b/ui/aura/test/mus/test_window_manager_client.h
@@ -41,6 +41,11 @@ class TestWindowManagerClient : public ui::mojom::WindowManagerClient {
                       bool is_primary_display,
                       Id window_id,
                       const SetDisplayRootCallback& callback) override;
+  void SetDisplayConfiguration(
+      const std::vector<display::Display>& displays,
+      std::vector<::ui::mojom::WmViewportMetricsPtr> viewport_metrics,
+      int64_t primary_display_id,
+      const SetDisplayConfigurationCallback& callback) override;
   void WmResponse(uint32_t change_id, bool response) override;
   void WmSetBoundsResponse(uint32_t change_id) override;
   void WmRequestClose(Id transport_window_id) override;