remove redundant CompletionRequestImpl class

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart

Index: pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
index f6f1f463b2765888c56d3f6b38133a9e3a0eb993..64e1b17334608ba210b1b62682d50664a105892d 100644
--- a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
+++ b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
@@ -136,7 +136,7 @@ abstract class DartCompletionContributorTest extends AbstractContextTest {
     AnalysisServer server = new AnalysisServerMock(
         searchEngine: searchEngine, resourceProvider: provider);
     CompletionRequestImpl baseRequest = new CompletionRequestImpl(
-        server, context, provider, testSource, completionOffset);
+        server, context, testSource, completionOffset);
     request = new DartCompletionRequestImpl.forRequest(baseRequest);
     Completer<List<CompletionSuggestion>> completer =
         new Completer<List<CompletionSuggestion>>();