Minor cleanup of error reporting in plugins

pkg/analyzer_plugin/lib/src/protocol/protocol_internal.dart

Index: pkg/analyzer_plugin/lib/src/protocol/protocol_internal.dart
diff --git a/pkg/analyzer_plugin/lib/src/protocol/protocol_internal.dart b/pkg/analyzer_plugin/lib/src/protocol/protocol_internal.dart
index 207755ee3742146cb9b2ff5be7ceff8f84926083..75d093c6601c21ba1f962f3c1cdf9df76514ca3b 100644
--- a/pkg/analyzer_plugin/lib/src/protocol/protocol_internal.dart
+++ b/pkg/analyzer_plugin/lib/src/protocol/protocol_internal.dart
@@ -441,9 +441,9 @@ class RequestDecoder extends JsonDecoder {
   /**
    * The request being deserialized.
    */
-  final Request _request;
+  final Request request;
 
-  RequestDecoder(this._request);
+  RequestDecoder(this.request);
 
   @override
   RefactoringKind get refactoringKind {
@@ -461,14 +461,14 @@ class RequestDecoder extends JsonDecoder {
       buffer.write(JSON.encode(actual));
       buffer.write('"');
     }
-    return new RequestFailure(RequestErrorFactory.invalidParameter(
-        _request, jsonPath, buffer.toString()));
+    return new RequestFailure(
+        RequestErrorFactory.invalidParameter(jsonPath, buffer.toString()));
   }
 
   @override
   dynamic missingKey(String jsonPath, String key) {
     return new RequestFailure(RequestErrorFactory.invalidParameter(
-        _request, jsonPath, 'Expected to contain key ${JSON.encode(key)}'));
+        jsonPath, 'Expected to contain key ${JSON.encode(key)}'));
   }
 }