Add summary support to CL 2647833002.

pkg/analyzer/lib/src/dart/element/element.dart

Index: pkg/analyzer/lib/src/dart/element/element.dart
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index 607946a9faebfdb9ce9a1cac035564a3420ea8db..88e6f41d5e9faa89d563957dc4b99e29cd90ec4b 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -7792,6 +7792,8 @@ abstract class PropertyInducingElementImpl
  * The context in which elements are resynthesized.
  */
 abstract class ResynthesizerContext {
+  bool get isStrongMode;
+
   /**
    * Build [ElementAnnotationImpl] for the given [UnlinkedExpr].
    */