Implement SharedQuadStateList StructTraits

components/mus/public/cpp/surfaces/tests/surface_unittest.cc

Index: components/mus/public/cpp/surfaces/tests/surface_unittest.cc
diff --git a/components/mus/public/cpp/surfaces/tests/surface_unittest.cc b/components/mus/public/cpp/surfaces/tests/surface_unittest.cc
index cdf539f359f05d9f95aa838078b870f6ecec9e77..aa5ed1c29b251652e3bfc64542293a65607b9872 100644
--- a/components/mus/public/cpp/surfaces/tests/surface_unittest.cc
+++ b/components/mus/public/cpp/surfaces/tests/surface_unittest.cc
@@ -152,7 +152,7 @@ TEST_F(SurfaceLibQuadTest, TextureQuadEmptyVertexOpacity) {
   mus_pass->id.layer_id = 1;
   mus_pass->id.index = 1u;
   mus_pass->quads.push_back(std::move(mus_texture_quad));
-  mus_pass->shared_quad_states.push_back(cc::SharedQuadState());
+  mus_pass->shared_quad_states.AllocateAndConstruct<cc::SharedQuadState>();
 
   std::unique_ptr<cc::RenderPass> pass =
       mus_pass.To<std::unique_ptr<cc::RenderPass>>();