1 files changed, 28 insertions, 0 deletions
diff --git a/dom/canvas/WebGLIpdl.h b/dom/canvas/WebGLIpdl.h
index 45a5c5ad64..4c81393b70 100644
--- a/dom/canvas/WebGLIpdl.h
+++ b/dom/canvas/WebGLIpdl.h
@@ -18,6 +18,8 @@
 #include "TupleUtils.h"
 #include "WebGLTypes.h"
 
+#include <memory>
+
 namespace mozilla {
 namespace webgl {
 
@@ -652,6 +654,32 @@ struct ParamTraits<mozilla::avec3<U>> final {
   }
 };
 
+// -
+
+template <class U>
+struct ParamTraits<std::optional<U>> final {
+  using T = std::optional<U>;
+
+  static void Write(MessageWriter* const writer, const T& in) {
+    WriteParam(writer, bool{in});
+    if (in) {
+      WriteParam(writer, *in);
+    }
+  }
+
+  static bool Read(MessageReader* const reader, T* const out) {
+    bool isSome;
+    if (!ReadParam(reader, &isSome)) return false;
+
+    if (!isSome) {
+      out->reset();
+      return true;
+    }
+    out->emplace();
+    return ReadParam(reader, &**out);
+  }
+};
+
 }  // namespace IPC
 
 #endif