Cherry-pick r44373, r44378, and r44275.

pkg/analysis_server/lib/src/operation/operation.dart

Index: pkg/analysis_server/lib/src/operation/operation.dart
diff --git a/pkg/analysis_server/lib/src/operation/operation.dart b/pkg/analysis_server/lib/src/operation/operation.dart
index 1433c904818c9b5bc9c4df1e32f0f573ae624b82..6c5732d307f52baaea92d2fcb2eb3db2db732d5a 100644
--- a/pkg/analysis_server/lib/src/operation/operation.dart
+++ b/pkg/analysis_server/lib/src/operation/operation.dart
@@ -5,6 +5,7 @@
 library operation;
 
 import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
@@ -13,6 +14,14 @@ import 'package:analyzer/src/generated/source.dart';
  */
 abstract class ServerOperation {
   /**
+   * The context for this operation.  Operations will be automatically
+   * de-queued when their context is destroyed.
+   */
+  final AnalysisContext context;
+
+  ServerOperation(this.context);
+
+  /**
    * Returns the priority of this operation.
    */
   ServerOperationPriority get priority;
@@ -63,6 +72,8 @@ class ServerOperationPriority {
  * before a change is applied to a [Source].
  */
 abstract class SourceSensitiveOperation extends ServerOperation {
+  SourceSensitiveOperation(AnalysisContext context) : super(context);
+
   /**
    * The given [source] is about to be changed.
    * Check if this [SourceSensitiveOperation] should be discarded.