Use more entities in program_builder, collector and registry

pkg/compiler/lib/src/deferred_load.dart

Index: pkg/compiler/lib/src/deferred_load.dart
diff --git a/pkg/compiler/lib/src/deferred_load.dart b/pkg/compiler/lib/src/deferred_load.dart
index 66e73c309adc9454905ccbf67559661f267a9644..088024907b23c7d832408b396ecad0559b1fea66 100644
--- a/pkg/compiler/lib/src/deferred_load.dart
+++ b/pkg/compiler/lib/src/deferred_load.dart
@@ -183,6 +183,16 @@ class DeferredLoadTask extends CompilerTask {
     return _elementToOutputUnit[element];
   }
 
+  /// Returns the [OutputUnit] where [element] belongs.
+  OutputUnit outputUnitForClass(ClassElement element) {
+    return outputUnitForElement(element);
+  }
+
+  /// Returns the [OutputUnit] where [element] belongs.
+  OutputUnit outputUnitForMember(MemberElement element) {
+    return outputUnitForElement(element);
+  }
+
   /// Direct access to the output-unit to element relation used for testing.
   OutputUnit getOutputUnitForElementForTesting(Element element) {
     return _elementToOutputUnit[element];
@@ -203,6 +213,10 @@ class DeferredLoadTask extends CompilerTask {
     return outputUnitForElement(element) != mainOutputUnit;
   }
 
+  bool isDeferredClass(ClassElement element) {
+    return outputUnitForElement(element) != mainOutputUnit;
+  }
+
   /// Returns the unique name for the deferred import of [prefix].
   String getImportDeferName(Spannable node, PrefixElement prefix) {
     String name =