Convert the utility process JSON parser into a Mojo service.

components/safe_json/public/interfaces/safe_json.mojom

Index: components/safe_json/public/interfaces/safe_json.mojom
diff --git a/gpu/ipc/common/mailbox.mojom b/components/safe_json/public/interfaces/safe_json.mojom
similarity index 57%
copy from gpu/ipc/common/mailbox.mojom
copy to components/safe_json/public/interfaces/safe_json.mojom
index 43df62bc82de045c0a154db72a35a517d7b883ee..599e6c45f29dd36a131c08c1be217f38f9d87d90 100644
--- a/gpu/ipc/common/mailbox.mojom
+++ b/components/safe_json/public/interfaces/safe_json.mojom
@@ -2,7 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module gpu.mojom;
+module safe_json.mojom;
 
 [Native]
-struct Mailbox;
+struct ListValue;
+
+interface SafeJsonParser {
+  Parse(string json) => (ListValue result, string? error);
+};