[Mojo] Add [Native] type traits for base::Values

mojo/common/test_common_custom_types.mojom

Index: mojo/common/test_common_custom_types.mojom
diff --git a/mojo/common/test_common_custom_types.mojom b/mojo/common/test_common_custom_types.mojom
index 0d2f165a8099e084075ac3b08aecdac5d92480b9..314f131a12e8bf8786c99533022a248c1c9c165d 100644
--- a/mojo/common/test_common_custom_types.mojom
+++ b/mojo/common/test_common_custom_types.mojom
@@ -10,3 +10,10 @@ interface TestFilePath {
   BounceFilePath(mojo.common.mojom.FilePath in)
       => (mojo.common.mojom.FilePath out);
 };
+
+interface TestValue {
+  BounceDictionaryValue(mojo.common.mojom.DictionaryValue in)
+      => (mojo.common.mojom.DictionaryValue out);
+  BounceListValue(mojo.common.mojom.ListValue in)
+      => (mojo.common.mojom.ListValue out);
+};