add parser parseAsync flag

pkg/analyzer/lib/src/generated/engine.dart

Index: pkg/analyzer/lib/src/generated/engine.dart
diff --git a/pkg/analyzer/lib/src/generated/engine.dart b/pkg/analyzer/lib/src/generated/engine.dart
index 0e762ee85f44cc22006e4ea33d1ca65045ef1462..f28be2e4e4b0cbbc936e37241b3ee258322eeddb 100644
--- a/pkg/analyzer/lib/src/generated/engine.dart
+++ b/pkg/analyzer/lib/src/generated/engine.dart
@@ -1047,6 +1047,11 @@ abstract class AnalysisOptions {
   bool get enableAssertMessage;
 
   /**
+   * Return `true` to if analysis is to enable async support.
+   */
+  bool get enableAsync;
+
+  /**
    * Return `true` to enable interface libraries (DEP 40).
    */
   bool get enableConditionalDirectives;
@@ -1155,6 +1160,11 @@ class AnalysisOptionsImpl implements AnalysisOptions {
   bool enableAssertMessage = false;
 
   /**
+   * A flag indicating whether analysis is to enable async support.
+   */
+  bool enableAsync = true;
+
+  /**
    * A flag indicating whether interface libraries are to be supported (DEP 40).
    */
   bool enableConditionalDirectives = false;
@@ -1249,6 +1259,7 @@ class AnalysisOptionsImpl implements AnalysisOptions {
     cacheSize = options.cacheSize;
     dart2jsHint = options.dart2jsHint;
     enableAssertMessage = options.enableAssertMessage;
+    enableAsync = options.enableAsync;
     enableStrictCallChecks = options.enableStrictCallChecks;
     enableGenericMethods = options.enableGenericMethods;
     enableSuperMixins = options.enableSuperMixins;