Clean up flags for conditional directives

pkg/analyzer/lib/src/task/options.dart

Index: pkg/analyzer/lib/src/task/options.dart
diff --git a/pkg/analyzer/lib/src/task/options.dart b/pkg/analyzer/lib/src/task/options.dart
index d3cc82f883fa24962395dca6be993fc6bfb3a8a7..47acf37f43b8e3feeb522f01ee908db72824abb7 100644
--- a/pkg/analyzer/lib/src/task/options.dart
+++ b/pkg/analyzer/lib/src/task/options.dart
@@ -48,6 +48,8 @@ class AnalyzerOptions {
   static const String enableGenericMethods = 'enableGenericMethods';
   static const String enableStrictCallChecks = 'enableStrictCallChecks';
   static const String enableSuperMixins = 'enableSuperMixins';
+
+  /// This option is deprecated.
   static const String enableConditionalDirectives =
       "enableConditionalDirectives";
   static const String errors = 'errors';
@@ -496,14 +498,6 @@ class _OptionsProcessor {
         context.analysisOptions = options;
       }
     }
-    if (feature == AnalyzerOptions.enableConditionalDirectives) {
-      if (isTrue(value)) {
-        AnalysisOptionsImpl options =
-            new AnalysisOptionsImpl.from(context.analysisOptions);
-        options.enableConditionalDirectives = true;
-        context.analysisOptions = options;
-      }
-    }
   }
 
   void setLanguageOptions(AnalysisContext context, Object configs) {