Avoid inlining constants that are used via a deferred import.

sdk/lib/_internal/compiler/implementation/deferred_load.dart

Index: sdk/lib/_internal/compiler/implementation/deferred_load.dart
diff --git a/sdk/lib/_internal/compiler/implementation/deferred_load.dart b/sdk/lib/_internal/compiler/implementation/deferred_load.dart
index 01552e10b998c135a0ac342ea3ad3b7a535950b1..3e69e99148f2f741c68619faab5ccdc6506932a4 100644
--- a/sdk/lib/_internal/compiler/implementation/deferred_load.dart
+++ b/sdk/lib/_internal/compiler/implementation/deferred_load.dart
@@ -11,9 +11,9 @@ import 'dart2jslib.dart' show
     Constant,
     ConstructedConstant,
     MessageKind,
+    DeferredConstant,
     StringConstant,
-    invariant,
-    Backend;
+    invariant;
 
 import 'dart_backend/dart_backend.dart' show
     DartBackend;
@@ -191,6 +191,13 @@ class DeferredLoadTask extends CompilerTask {
     return outputUnitForElement(e1) == outputUnitForElement(e2);
   }
 
+  void registerConstantDeferredUse(DeferredConstant constant,
+                                   PrefixElement prefix) {
+    OutputUnit outputUnit = new OutputUnit();
+    outputUnit.imports.add(prefix.deferredImport);
+    _constantToOutputUnit[constant] = outputUnit;
+  }
+
   /// Mark that [import] is part of the [OutputputUnit] for [element].
   ///
   /// [element] can be either a [Constant] or an [Element].