Start tracking all registered elements in one big full function set

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 55895480aa5a3cc4626612e512e5aeb3ae72b918..9d0ab9b313b6811253ce85a3385f3c4fc1fe6cec 100644
--- a/sdk/lib/_internal/compiler/implementation/enqueue.dart
+++ b/sdk/lib/_internal/compiler/implementation/enqueue.dart
@@ -120,9 +120,12 @@ abstract class Enqueuer {
     if (isProcessed(member)) return;
     if (!member.isInstanceMember()) return;
     if (member.isField()) {
-      // Native fields need to go into instanceMembersByName as they are virtual
-      // instantiation points and escape points.
-      // Test the enclosing class, since the metadata has not been parsed yet.
+      // Fields are implicitly used by the constructor of the
+      // instantiated class they are part of.
+      compiler.world.registerUsedElement(member);
+      // Native fields need to go into instanceMembersByName as they
+      // are virtual instantiation points and escape points. Test the
+      // enclosing class, since the metadata has not been parsed yet.
       if (!member.enclosingElement.isNative()) return;
     }