Improve the mirror support for deferred loading.

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

Index: sdk/lib/_internal/compiler/implementation/enqueue.dart
diff --git a/sdk/lib/_internal/compiler/implementation/enqueue.dart b/sdk/lib/_internal/compiler/implementation/enqueue.dart
index 47150a055febcbc1177a5ad64f11e637e76a83cf..9e695843ad4f5f73274abbcbf441d80ecdd81414 100644
--- a/sdk/lib/_internal/compiler/implementation/enqueue.dart
+++ b/sdk/lib/_internal/compiler/implementation/enqueue.dart
@@ -365,7 +365,7 @@ abstract class Enqueuer {
     task.ensureAllElementsByName();
     for (Link link in task.allElementsByName.values) {
       for (Element element in link) {
-        pretendElementWasUsed(element, compiler.globalDependencies);
+        pretendElementWasUsed(element, compiler.mirrorDependencies);
       }
     }
     hasEnqueuedEverything = true;
@@ -378,7 +378,7 @@ abstract class Enqueuer {
     if (hasEnqueuedReflectiveStaticFields) return;
     hasEnqueuedReflectiveStaticFields = true;
     for (Element element in elements) {
-      pretendElementWasUsed(element, compiler.globalDependencies);
+      pretendElementWasUsed(element, compiler.mirrorDependencies);
     }
   }