move context id constant to AnalysisServer

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 7af6afdc1ea2e412136784576dc2777641049bff..1bc01d584eacc2664d559b8d0b8db4b6433931e7 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -24,6 +24,11 @@ class AnalysisServer {
   static const String ERROR_NOTIFICATION_NAME = 'context.errors';
 
   /**
+   * The name of the contextId parameter.
+   */
+  static const String CONTEXT_ID_PARAM = 'contextId';
+
+  /**
    * The name of the parameter whose value is a list of errors.
    */
   static const String ERRORS_PARAM = 'errors';