Add file identifiers to summaries.

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

Index: pkg/analyzer/lib/src/summary/idl.dart
diff --git a/pkg/analyzer/lib/src/summary/idl.dart b/pkg/analyzer/lib/src/summary/idl.dart
index 9d840b96997564d40d1007e4bc49360d4bac0c37..28a8787a2b4059bbcafe15597242b594398abdf2 100644
--- a/pkg/analyzer/lib/src/summary/idl.dart
+++ b/pkg/analyzer/lib/src/summary/idl.dart
@@ -42,7 +42,7 @@
 library analyzer.tool.summary.idl;
 
 import 'base.dart' as base;
-import 'base.dart' show Id;
+import 'base.dart' show Id, TopLevel;
 import 'format.dart' as generated;
 
 /**
@@ -53,12 +53,6 @@ import 'format.dart' as generated;
 const informative = null;
 
 /**
- * Annotation describing a class which can be the top level object in an
- * encoded summary.
- */
-const topLevel = null;
-
-/**
  * Summary information about a reference to a an entity such as a type, top
  * level executable, or executable within a class.
  */
@@ -197,7 +191,7 @@ abstract class LinkedExportName extends base.SummaryClass {
 /**
  * Linked summary of a library.
  */
-@topLevel
+@TopLevel('LLib')
 abstract class LinkedLibrary extends base.SummaryClass {
   factory LinkedLibrary.fromBuffer(List<int> buffer) =>
       generated.readLinkedLibrary(buffer);
@@ -356,7 +350,7 @@ abstract class LinkedUnit extends base.SummaryClass {
 /**
  * Summary information about a package.
  */
-@topLevel
+@TopLevel('PBdl')
 abstract class PackageBundle extends base.SummaryClass {
   factory PackageBundle.fromBuffer(List<int> buffer) =>
       generated.readPackageBundle(buffer);
@@ -1648,7 +1642,7 @@ abstract class UnlinkedPublicName extends base.SummaryClass {
  * library's public namespace.  This is the subset of [UnlinkedUnit] that is
  * required from dependent libraries in order to perform prelinking.
  */
-@topLevel
+@TopLevel('UPNS')
 abstract class UnlinkedPublicNamespace extends base.SummaryClass {
   factory UnlinkedPublicNamespace.fromBuffer(List<int> buffer) =>
       generated.readUnlinkedPublicNamespace(buffer);
@@ -1784,7 +1778,7 @@ abstract class UnlinkedTypeParam extends base.SummaryClass {
 /**
  * Unlinked summary information about a compilation unit ("part file").
  */
-@topLevel
+@TopLevel('UUnt')
 abstract class UnlinkedUnit extends base.SummaryClass {
   factory UnlinkedUnit.fromBuffer(List<int> buffer) =>
       generated.readUnlinkedUnit(buffer);