Add propagated types to summary files.

pkg/analyzer/lib/src/summary/summarize_ast.dart

Index: pkg/analyzer/lib/src/summary/summarize_ast.dart
diff --git a/pkg/analyzer/lib/src/summary/summarize_ast.dart b/pkg/analyzer/lib/src/summary/summarize_ast.dart
index 1e62d4e4d4bfd79c086a71785335cb7f7b28b004..71a8395ba642c33e21f7bdf258a3513e1333e809 100644
--- a/pkg/analyzer/lib/src/summary/summarize_ast.dart
+++ b/pkg/analyzer/lib/src/summary/summarize_ast.dart
@@ -221,6 +221,16 @@ class _SummarizeAstVisitor extends SimpleAstVisitor {
   UnlinkedDocumentationCommentBuilder libraryDocumentationComment;
 
   /**
+   * The number of slot ids which have been assigned to this compilation unit.
+   */
+  int numSlots = 0;
+
+  /**
+   * Create a slot id for storing a propagated or inferred type.
+   */
+  int assignTypeSlot() => ++numSlots;
+
+  /**
    * Build a [_Scope] object containing the names defined within the body of a
    * class declaration.
    */
@@ -611,6 +621,10 @@ class _SummarizeAstVisitor extends SimpleAstVisitor {
           b.constExpr = serializeConstExpr(initializer);
         }
       }
+      if (variable.initializer != null &&
+          (variables.isFinal || variables.isConst)) {
+        b.propagatedTypeSlot = assignTypeSlot();
+      }
       this.variables.add(b);
     }
   }