Create a NullErrorReporter to use when errors don't need to be recorded.

pkg/analyzer/lib/src/generated/constant.dart

Index: pkg/analyzer/lib/src/generated/constant.dart
diff --git a/pkg/analyzer/lib/src/generated/constant.dart b/pkg/analyzer/lib/src/generated/constant.dart
index b121892a962931fee5df1e23224b7ba8c5487346..72da2881ee8f70e94fee0bac81e27439e61e4f64 100644
--- a/pkg/analyzer/lib/src/generated/constant.dart
+++ b/pkg/analyzer/lib/src/generated/constant.dart
@@ -209,7 +209,7 @@ class ConstantEvaluator {
 
   EvaluationResult evaluate(Expression expression) {
     RecordingErrorListener errorListener = new RecordingErrorListener();
-    ErrorReporter errorReporter = new ErrorReporter(errorListener, _source);
+    ErrorReporter errorReporter = new ErrorReporterImpl(errorListener, _source);
     DartObjectImpl result = expression.accept(new ConstantVisitor.con1(_typeProvider, errorReporter));
     if (result != null) {
       return EvaluationResult.forValue(result);
@@ -547,7 +547,7 @@ class ConstantValueComputer {
       VariableDeclaration declaration = constNode;
       Element element = declaration.element;
       RecordingErrorListener errorListener = new RecordingErrorListener();
-      ErrorReporter errorReporter = new ErrorReporter(errorListener, element.source);
+      ErrorReporter errorReporter = new ErrorReporterImpl(errorListener, element.source);
       DartObjectImpl dartObject = declaration.initializer.accept(createConstantVisitor(errorReporter));
       (element as VariableElementImpl).evaluationResult = new EvaluationResultImpl.con2(dartObject, errorListener.errors);
     } else if (constNode is InstanceCreationExpression) {
@@ -561,7 +561,7 @@ class ConstantValueComputer {
       }
       RecordingErrorListener errorListener = new RecordingErrorListener();
       CompilationUnit sourceCompilationUnit = expression.getAncestor((node) => node is CompilationUnit);
-      ErrorReporter errorReporter = new ErrorReporter(errorListener, sourceCompilationUnit.element.source);
+      ErrorReporter errorReporter = new ErrorReporterImpl(errorListener, sourceCompilationUnit.element.source);
       ConstantVisitor constantVisitor = createConstantVisitor(errorReporter);
       DartObjectImpl result = _evaluateConstructorCall(constNode, expression.argumentList.arguments, constructor, constantVisitor, errorReporter);
       expression.evaluationResult = new EvaluationResultImpl.con2(result, errorListener.errors);
@@ -577,7 +577,7 @@ class ConstantValueComputer {
         Expression defaultValue = parameter.defaultValue;
         if (defaultValue != null) {
           RecordingErrorListener errorListener = new RecordingErrorListener();
-          ErrorReporter errorReporter = new ErrorReporter(errorListener, element.source);
+          ErrorReporter errorReporter = new ErrorReporterImpl(errorListener, element.source);
           DartObjectImpl dartObject = defaultValue.accept(createConstantVisitor(errorReporter));
           (element as ParameterElementImpl).evaluationResult = new EvaluationResultImpl.con2(dartObject, errorListener.errors);
         }