Remove internal uses of mojo::Array and mojo::WTFArray.

mojo/public/cpp/bindings/tests/struct_traits_unittest.cc

Index: mojo/public/cpp/bindings/tests/struct_traits_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/struct_traits_unittest.cc b/mojo/public/cpp/bindings/tests/struct_traits_unittest.cc
index cd698af9eb2471f90336cc19b9a7227ba4b22d40..4c06267c6583135c8c2bc7166960041a5733cef1 100644
--- a/mojo/public/cpp/bindings/tests/struct_traits_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/struct_traits_unittest.cc
@@ -459,7 +459,7 @@ TEST_F(StructTraitsTest, SerializeStructWithTraits) {
   input.get_mutable_struct_map()["hello"] = NestedStructWithTraitsImpl(1024);
   input.get_mutable_struct_map()["world"] = NestedStructWithTraitsImpl(2048);
 
-  mojo::Array<uint8_t> data = StructWithTraits::Serialize(&input);
+  auto data = StructWithTraits::Serialize(&input);
   StructWithTraitsImpl output;
   ASSERT_TRUE(StructWithTraits::Deserialize(std::move(data), &output));