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

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

Index: pkg/analyzer_plugin/lib/src/utilities/completion/completion_core.dart
diff --git a/pkg/analyzer_plugin/lib/src/utilities/completion/completion_core.dart b/pkg/analyzer_plugin/lib/src/utilities/completion/completion_core.dart
index d86c2faf0646b8717b88309502936896d53be929..4f68255a4139cf337576abe23d1c0af8db6fbdf4 100644
--- a/pkg/analyzer_plugin/lib/src/utilities/completion/completion_core.dart
+++ b/pkg/analyzer_plugin/lib/src/utilities/completion/completion_core.dart
@@ -65,6 +65,12 @@ class CompletionCollectorImpl implements CompletionCollector {
   void addSuggestion(CompletionSuggestion suggestion) {
     suggestions.add(suggestion);
   }
+
+  @override
+  bool get offsetIsSet => offset != null;
+
+  @override
+  int get suggestionsLength => suggestions.length;
 }
 
 /**