Pass AnalysisOptions into SdkCreator, disable changing afterwards.

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

Index: pkg/analyzer/lib/src/generated/sdk.dart
diff --git a/pkg/analyzer/lib/src/generated/sdk.dart b/pkg/analyzer/lib/src/generated/sdk.dart
index 0670b7c0895a5da0c969414274cea676a0bcde62..27577b84d465807ade8d6b10b753e37083b91a6c 100644
--- a/pkg/analyzer/lib/src/generated/sdk.dart
+++ b/pkg/analyzer/lib/src/generated/sdk.dart
@@ -14,9 +14,10 @@ import 'package:analyzer/src/generated/source.dart'
     show ContentCache, Source, UriKind;
 
 /**
- * A function used to create a new DartSdk
+ * A function used to create a new DartSdk with the given [options]. If the
+ * passed [options] are `null`, then default options are used.
  */
-typedef DartSdk SdkCreator();
+typedef DartSdk SdkCreator(AnalysisOptions options);
 
 /**
  * A Dart SDK installed in a specified location.
@@ -126,9 +127,8 @@ class DartSdkManager {
     int encoding = options.encodeCrossContextOptions();
     DartSdk sdk = sdkMap[encoding];
     if (sdk == null) {
-      sdk = sdkCreator();
+      sdk = sdkCreator(options);
       sdkMap[encoding] = sdk;
-      sdk.context.analysisOptions.setCrossContextOptionsFrom(options);
     }
     return sdk;
   }