Add IR nodes needed for deferred loading.

pkg/kernel/lib/binary/ast_from_binary.dart

Index: pkg/kernel/lib/binary/ast_from_binary.dart
diff --git a/pkg/kernel/lib/binary/ast_from_binary.dart b/pkg/kernel/lib/binary/ast_from_binary.dart
index 8c940f69fe5586c80a9aab09cc9354c5f8db56a9..c4fc3ef034bf2466d5bdcea7cb9691e34a5e8c91 100644
--- a/pkg/kernel/lib/binary/ast_from_binary.dart
+++ b/pkg/kernel/lib/binary/ast_from_binary.dart
@@ -187,8 +187,7 @@ class BinaryBuilder {
       readLibrary();
     }
     var mainMethod = readMemberReference(allowNull: true);
-    return new Program(importTable, uriToSource)
-      ..mainMethod = mainMethod;
+    return new Program(importTable, uriToSource)..mainMethod = mainMethod;
   }
 
   Map<String, Source> readUriToSource() {
@@ -226,6 +225,11 @@ class BinaryBuilder {
     return importTable[index];
   }
 
+  DeferredImport readDeferredImportReference() {
+    int index = readUInt();
+    return _currentLibrary.deferredImports[index];
+  }
+
   Class readClassReference({bool allowNull: false}) {
     int tag = readByte();
     if (tag == Tag.NullReference) {
@@ -292,6 +296,7 @@ class BinaryBuilder {
     // TODO(jensj): We currently save (almost the same) uri twice.
     _currentLibrary.fileUri = readUriReference();
 
+    _readDeferredImports(_currentLibrary);
     _fillLazilyLoadedList(_currentLibrary.classes, (int tag, int index) {
       readClass(loader.getClassReference(_currentLibrary, tag, index), tag);
     });
@@ -306,6 +311,19 @@ class BinaryBuilder {
     debugPath.removeLast();
   }
 
+  void _readDeferredImports(Library library) {
+    int count = readUInt();
+    library.deferredImports.length = count;
+    for (int i = 0; i < count; ++i) {
+      var importNode = _readDeferredImport();
+      library.deferredImports.add(importNode..parent = library);
+    }
+  }
+
+  DeferredImport _readDeferredImport() {
+    return new DeferredImport(readLibraryReference(), readStringReference());
+  }
+
   void readClass(Class node, int tag) {
     assert(node != null);
     switch (tag) {
@@ -530,6 +548,10 @@ class BinaryBuilder {
         ? tagByte
         : (tagByte & Tag.SpecializedTagMask);
     switch (tag) {
+      case Tag.LoadLibrary:
+        return new LoadLibrary(readDeferredImportReference());
+      case Tag.CheckLibraryIsLoaded:
+        return new CheckLibraryIsLoaded(readDeferredImportReference());
       case Tag.InvalidExpression:
         return new InvalidExpression();
       case Tag.VariableGet: