restructure internal request to implement CompletionRequest API,

pkg/analysis_server/lib/src/domain_completion.dart

Index: pkg/analysis_server/lib/src/domain_completion.dart
diff --git a/pkg/analysis_server/lib/src/domain_completion.dart b/pkg/analysis_server/lib/src/domain_completion.dart
index 8da57abad0d9d3f66328a0da7297171823b09482..cd9b426e91145e37c7061123fb88cd4ae7994f4d 100644
--- a/pkg/analysis_server/lib/src/domain_completion.dart
+++ b/pkg/analysis_server/lib/src/domain_completion.dart
@@ -6,6 +6,8 @@ library domain.completion;
 
 import 'dart:async';
 
+import 'package:analysis_server/completion/completion_core.dart'
+    show CompletionRequest;
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
@@ -23,6 +25,11 @@ export 'package:analysis_server/src/services/completion/completion_manager.dart'
  */
 class CompletionDomainHandler implements RequestHandler {
   /**
+   * The maximum number of performance measurements to keep.
+   */
+  static const int performanceListMaxLength = 50;
+
+  /**
    * The analysis server that is using this handler to process requests.
    */
   final AnalysisServer server;
@@ -61,11 +68,6 @@ class CompletionDomainHandler implements RequestHandler {
       new List<CompletionPerformance>();
 
   /**
-   * The maximum number of performance measurements to keep.
-   */
-  static const int performanceListMaxLength = 50;
-
-  /**
    * Performance for the last priority change event.
    */
   CompletionPerformance computeCachePerformance;
@@ -185,7 +187,7 @@ class CompletionDomainHandler implements RequestHandler {
       manager = completionManagerFor(context, source);
     }
     CompletionRequest completionRequest =
-        new CompletionRequest(params.offset, performance);
+        new CompletionRequestImpl(server, context, source, params.offset);
     int notificationCount = 0;
     manager.results(completionRequest).listen((CompletionResult result) {
       ++notificationCount;