Change to accommade Angular plugin and finalize removal of dependency to analysis_server

pkg/analyzer_plugin/lib/utilities/completion/completion_core.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer_plugin/protocol/protocol.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
@@ skipping 28 matching lines @@
    * Set the offset of the region of text that should be replaced by the
    * selected completion suggestion.
    *
    * The offset can only be set once and applies to all of the suggestions.
    * Hence, this setter throws a [StateError] if the offset has already been
    * set.
    */
   void set offset(int offset);
 
   /**
+   * Indicates if the collector's offset has been set (and ultimately the
+   * length too).
+   */
+  bool get offsetIsSet;
+
+  /**
+   * Returns length of suggestions currently held.
+   */
+  int get suggestionsLength;
+
+  /**
    * Record the given completion [suggestion].
    */
   void addSuggestion(CompletionSuggestion suggestion);
 }
 
 /**
  * An object used to produce completion suggestions.
  *
  * Clients may implement this class when implementing plugins.
  */
@@ skipping 38 matching lines @@
           await contributor.computeSuggestions(request, collector);
         } catch (exception, stackTrace) {
           notifications.add(new PluginErrorParams(
                   false, exception.toString(), stackTrace.toString())
               .toNotification());
         }
       }
     } on AbortCompletion {
       return new GeneratorResult(null, notifications);
     }
+    if (collector.suggestions.isEmpty) {

[mfairhurst, 2017/06/13 20:31:39]

Should this instead check 'offsetIsSet'? And, what's the need for "no results"
to be equivalent to setting the completion offset and length to anything? Seems
reasonable, but also a bit strange.

[maxkim, 2017/06/13 20:49:21]

Ah that's right, I added this block before adding that variable. Somewhere in an
upper level, if the response has null offset/length, it crashes. Since that's
outside of the scope of where I'm comfortable contributing to, this is a
temporary yet effective bandaid.

+      collector
+        ..offset = request.offset
+        ..length = 0;
+    }
     CompletionGetSuggestionsResult result = new CompletionGetSuggestionsResult(
         collector.offset, collector.length, collector.suggestions);

[Brian Wilkerson, 2017/06/13 20:50:19]

I don't understand what the length of the suggestions has to do with anything
either. Perhaps we should just pass in `collector.offset ?? request.offset,
collector.length ?? 0`?

[maxkim, 2017/06/13 21:11:40]

This is following the assumption that if suggestions is empty, then it is
probable that length and offset hasn't been set. I will change it to ??=
assignments.

     return new GeneratorResult(result, notifications);
   }
 }
 
 /**
  * The information about a requested list of completions.
  *
  * Clients may not extend, implement or mix-in this class.
  */
 abstract class CompletionRequest {
@@ skipping 12 matching lines @@
    * The analysis result for the file in which the completion is being
    * requested.
    */
   ResolveResult get result;
 
   /**
    * Throw an [AbortCompletion] if the completion request has been aborted.
    */
   void checkAborted();
 }