Fix bug where temp output structs weren't initialized.

Bug: 357798108
Change-Id: Ia49a2f982614f12ad3fbe80a119e335e0088001c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/201495
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jim Blackler <jimblackler@google.com>

generator/templates/art/methods.cpp

diff --git a/generator/templates/art/methods.cpp b/generator/templates/art/methods.cpp
index 67d1538..770e797 100644
--- a/generator/templates/art/methods.cpp
+++ b/generator/templates/art/methods.cpp
@@ -143,7 +143,7 @@
     {% else %}
         {% if _kotlin_return.annotation == '*' %}
             //* Make a native container to accept the data output via parameter.
-            {{ as_cType(_kotlin_return.type.name) }} out;
+            {{ as_cType(_kotlin_return.type.name) }} out = {};
             args.{{ _kotlin_return.name.get() }} = &out;
         {% endif %}
         {{ 'auto result =' if _kotlin_return.type.name.get() != 'void' }}