Add missing memory include

Change-Id: Icab0d32f199d4b0f95e2c1ebcd9ae9ea9ec7b61c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/19020
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
diff --git a/src/writer/wgsl/generator_impl_test.cc b/src/writer/wgsl/generator_impl_test.cc
index 814f214..7bd50f6 100644
--- a/src/writer/wgsl/generator_impl_test.cc
+++ b/src/writer/wgsl/generator_impl_test.cc
@@ -14,6 +14,8 @@
 
 #include "src/writer/wgsl/generator_impl.h"
 
+#include <memory>
+
 #include "gtest/gtest.h"
 
 namespace tint {