Mojom compiler frontend: Change the type of the |offset| field to uint32.

mojo/dart/packages/_mojo_for_test_only/lib/sample/sample_interfaces.mojom.dart

Index: mojo/dart/packages/_mojo_for_test_only/lib/sample/sample_interfaces.mojom.dart
diff --git a/mojo/dart/packages/_mojo_for_test_only/lib/sample/sample_interfaces.mojom.dart b/mojo/dart/packages/_mojo_for_test_only/lib/sample/sample_interfaces.mojom.dart
index bd17e1b43a8f4e137edded8298f8f28dabb1766c..1c91b0d847899dd3ef5f76223de2b3037364a401 100644
--- a/mojo/dart/packages/_mojo_for_test_only/lib/sample/sample_interfaces.mojom.dart
+++ b/mojo/dart/packages/_mojo_for_test_only/lib/sample/sample_interfaces.mojom.dart
@@ -2458,7 +2458,7 @@ mojom_types.RuntimeTypeInfo  _initRuntimeTypeInfo() {
   // serializedRuntimeTypeInfo contains the bytes of the Mojo serialization of
   // a mojom_types.RuntimeTypeInfo struct describing the Mojom types in this
   // file. The string contains the base64 encoding of the gzip-compressed bytes.
-  var serializedRuntimeTypeInfo = "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";
+  var serializedRuntimeTypeInfo = "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";
 
   // Deserialize RuntimeTypeInfo
   var bytes = BASE64.decode(serializedRuntimeTypeInfo);