SurfaceAggregator should check whether output is secure when drawin

ash/mus/stub_context_factory.h

Index: ash/mus/stub_context_factory.h
diff --git a/ash/mus/stub_context_factory.h b/ash/mus/stub_context_factory.h
index 1c68720b88f2cff75ff140978312c1201b8a9d87..7f3a3251d8c2674664707eeabaa6abcb71a5eb16 100644
--- a/ash/mus/stub_context_factory.h
+++ b/ash/mus/stub_context_factory.h
@@ -43,6 +43,7 @@ class StubContextFactory : public ui::ContextFactory {
                      const gfx::Size& size) override;
   void SetAuthoritativeVSyncInterval(ui::Compositor* compositor,
                                      base::TimeDelta interval) override {}
+  void SetOutputIsSecure(ui::Compositor* compositor, bool secure) override {}
 
   uint32_t next_surface_id_namespace_;
   std::unique_ptr<cc::SingleThreadTaskGraphRunner> task_graph_runner_;