restructure internal request to implement CompletionRequest API,

pkg/analysis_server/lib/src/services/completion/completion_manager.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library services.completion.manager;
 
 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/protocol.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
+import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * [CompletionCache] contains information about the prior code completion
  * for use in the next code completion.
  */
 abstract class CompletionCache {
 
   /**
@@ skipping 101 matching lines @@
   String snippet = '';
   int notificationCount = -1;
   int suggestionCountFirst = -1;
   int suggestionCountLast = -1;
   Duration _firstNotification;
 
   CompletionPerformance() {
     _stopwatch.start();
   }
 
-  void setContentsAndOffset(String contents, int offset) {
-    snippet = _computeSnippet(contents, offset);
-  }
-
   int get elapsedInMilliseconds =>
       operations.length > 0 ? operations.last.elapsed.inMilliseconds : 0;
 
   int get firstNotificationInMilliseconds =>
       _firstNotification != null ? _firstNotification.inMilliseconds : 0;
 
   String get startTimeAndMs => '${start.millisecondsSinceEpoch} - $start';
 
   String get suggestionCount {
     if (notificationCount < 1) return '';
@@ skipping 27 matching lines @@
 
   void logFirstNotificationComplete(String tag) {
     _firstNotification = _stopwatch.elapsed;
     _logDuration(tag, _firstNotification);
   }
 
   void logStartTime(String tag) {
     _startTimes[tag] = _stopwatch.elapsed;
   }
 
+  void setContentsAndOffset(String contents, int offset) {
+    snippet = _computeSnippet(contents, offset);
+  }
+
   void _logDuration(String tag, Duration elapsed) {
     operations.add(new OperationPerformance(tag, elapsed));
   }
 
   static String _computeSnippet(String contents, int offset) {
     if (contents == null ||
         offset == null ||
         offset < 0 ||
         contents.length < offset) {
       return '???';
@@ skipping 16 matching lines @@
     }
     String prefix = contents.substring(start, offset);
     String suffix = contents.substring(offset, end);
     return '$prefix^$suffix';
   }
 }
 
 /**
  * Encapsulates information specific to a particular completion request.
  */
-class CompletionRequest {
+class CompletionRequestImpl implements CompletionRequest {
+
   /**
-   * The offset within the source at which the completion is requested.
+   * The underlying analysis server for this completion request.
    */
+  final AnalysisServer server;
+
+  @override
+  final AnalysisContext context;
+
+  @override
+  final Source source;
+
+  @override
   final int offset;
 
-  /**
-   * Performance measurements for this particular request.
-   */
-  final CompletionPerformance performance;
+  CompletionRequestImpl(this.server, this.context, this.source, this.offset);
 
-  CompletionRequest(this.offset, this.performance);
+  @override
+  ResourceProvider get provider => server.resourceProvider;
 }
 
 /**
  * Code completion result generated by an [CompletionManager].
  */
 class CompletionResult {
 
   /**
    * The length of the text to be replaced if the remainder of the identifier
    * containing the cursor is to be replaced when the suggestion is applied
@@ skipping 43 matching lines @@
    */
   final String name;
 
   /**
    * The elapse time or `null` if undefined.
    */
   final Duration elapsed;
 
   OperationPerformance(this.name, this.elapsed);
 }