Generate less code when importing dart:mirrors.

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

Index: dart/sdk/lib/_internal/compiler/implementation/compiler.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/compiler.dart b/dart/sdk/lib/_internal/compiler/implementation/compiler.dart
index 177eefe4421865b1606816a6171c4e9f15d04481..6547fbf872bdd2b76b7b6dd1a08e93f817fb8bb4 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/compiler.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/compiler.dart
@@ -140,7 +140,7 @@ abstract class Backend {
   void registerThrowExpression(TreeElements elements) {}
   void registerLazyField(TreeElements elements) {}
   void registerTypeVariableExpression(TreeElements elements) {}
-  void registerTypeLiteral(TreeElements elements) {}
+  void registerTypeLiteral(Element element, TreeElements elements) {}
   void registerStackTraceInCatch(TreeElements elements) {}
   void registerIsCheck(DartType type,
                        Enqueuer enqueuer,
@@ -157,6 +157,9 @@ abstract class Backend {
   void registerRequiredType(DartType type, Element enclosingElement) {}
   void registerClassUsingVariableExpression(ClassElement cls) {}
 
+  void registerConstSymbol(String name, TreeElements elements) {}
+  void registerNewSymbol(TreeElements elements) {}
+
   bool isNullImplementation(ClassElement cls) {
     return cls == compiler.nullClass;
   }
@@ -183,9 +186,14 @@ abstract class Backend {
     return classElement == compiler.objectClass;
   }
 
-  void enableMirrors() {}
-
   void registerStaticUse(Element element, Enqueuer enqueuer) {}
+
+  void onLibraryScanned(LibraryElement library, Uri uri) {}
+
+  void registerMetadataInstantiatedClass(ClassElement element,
+                                         TreeElements elements) {}
+  void registerMetadataStaticUse(Element element) {}
+  void registerMetadataGetOfStaticFunction(FunctionElement element) {}
 }
 
 /**
@@ -529,8 +537,6 @@ abstract class Compiler implements DiagnosticListener {
 
   bool get hasBuildId => buildId != UNDETERMINED_BUILD_ID;
 
-  bool get mirrorsEnabled => mirrorSystemClass != null;
-
   bool get analyzeAll => analyzeAllFlag || compileAll;
 
   bool get compileAll => false;
@@ -674,11 +680,10 @@ abstract class Compiler implements DiagnosticListener {
     }
     if (uri == Uri.parse('dart:mirrors')) {
       mirrorSystemClass = library.find(const SourceString('MirrorSystem'));
-      backend.enableMirrors();
-      metadataHandler = constantHandler;
     } else if (uri == Uri.parse('dart:_collection-dev')) {
       symbolImplementationClass = library.find(const SourceString('Symbol'));
     }
+    backend.onLibraryScanned(library, uri);
   }
 
   void onClassResolved(ClassElement cls) {
@@ -866,7 +871,6 @@ abstract class Compiler implements DiagnosticListener {
     // Elements required by enqueueHelpers are global dependencies
     // that are not pulled in by a particular element.
     backend.enqueueHelpers(enqueuer.resolution, globalDependencies);
-    resolveReflectiveDataIfNeeded();
     processQueue(enqueuer.resolution, main);
     enqueuer.resolution.logSummary(log);
 
@@ -912,17 +916,6 @@ abstract class Compiler implements DiagnosticListener {
     checkQueues();
   }
 
-  void resolveReflectiveDataIfNeeded() {
-    // Only need reflective data when dart:mirrors is loaded.
-    if (!mirrorsEnabled) return;
-
-    for (LibraryElement library in libraries.values) {
-      for (Link link = library.metadata; !link.isEmpty; link = link.tail) {
-        link.head.ensureResolved(this);
-      }
-    }
-  }
-
   void fullyEnqueueLibrary(LibraryElement library, Enqueuer world) {
     void enqueueAll(Element element) {
       fullyEnqueueTopLevelElement(element, world);