Reorganize InheritedRefenenceContributor to serve angular completion

pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart

Index: pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
diff --git a/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart b/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
index bec47b407f53bb8b4fbe6f284febdab50be6b5ac..e9d4574e824c8e300d4a39fed82adca895507419 100644
--- a/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
+++ b/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
@@ -100,6 +100,12 @@ abstract class DartCompletionRequest extends CompletionRequest {
   DartType get objectType;
 
   /**
+   * The [OpType] which describes which types of suggestions would fit the
+   * request.
+   */
+  OpType get opType;
+
+  /**
    * Return the [SourceFactory] of the request.
    */
   SourceFactory get sourceFactory;