Revert "Remove WorldImpact from caches when no longer needed."

pkg/compiler/lib/src/universe/world_impact.dart

Index: pkg/compiler/lib/src/universe/world_impact.dart
diff --git a/pkg/compiler/lib/src/universe/world_impact.dart b/pkg/compiler/lib/src/universe/world_impact.dart
index 569312bbe9910aa4965be9cbb5d2382f1242186b..fe7822dbb57a4f8d8472ffe5486186d85d0d59d6 100644
--- a/pkg/compiler/lib/src/universe/world_impact.dart
+++ b/pkg/compiler/lib/src/universe/world_impact.dart
@@ -34,12 +34,6 @@ class WorldImpact {
 
   Iterable<TypeUse> get typeUses => const <TypeUse>[];
 
-  void apply(WorldImpactVisitor visitor) {
-    staticUses.forEach(visitor.visitStaticUse);
-    dynamicUses.forEach(visitor.visitDynamicUse);
-    typeUses.forEach(visitor.visitTypeUse);
-  }
-
   String toString() => dump(this);
 
   static String dump(WorldImpact worldImpact) {
@@ -160,12 +154,6 @@ class TransformedWorldImpact implements WorldImpact {
     return _staticUses != null ? _staticUses : worldImpact.staticUses;
   }
 
-  void apply(WorldImpactVisitor visitor) {
-    staticUses.forEach(visitor.visitStaticUse);
-    dynamicUses.forEach(visitor.visitDynamicUse);
-    typeUses.forEach(visitor.visitTypeUse);
-  }
-
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.write('TransformedWorldImpact($worldImpact)');
@@ -173,72 +161,3 @@ class TransformedWorldImpact implements WorldImpact {
     return sb.toString();
   }
 }
-
-/// Constant used to denote a specific use of a [WorldImpact].
-class ImpactUseCase {
-  final String name;
-
-  const ImpactUseCase(this.name);
-
-  String toString() => 'ImpactUseCase($name)';
-}
-
-/// Strategy used for processing [WorldImpact] object in various use cases.
-class ImpactStrategy {
-  const ImpactStrategy();
-
-  /// Applies [impact] to [visitor] for the [impactUseCase] of [element].
-  void visitImpact(Element element,
-                   WorldImpact impact,
-                   WorldImpactVisitor visitor,
-                   ImpactUseCase impactUseCase) {
-    // Apply unconditionally.
-    impact.apply(visitor);
-  }
-}
-
-/// Visitor used to process the uses of a [WorldImpact].
-abstract class WorldImpactVisitor {
-  void visitStaticUse(StaticUse staticUse);
-  void visitDynamicUse(DynamicUse dynamicUse);
-  void visitTypeUse(TypeUse typeUse);
-}
-
-// TODO(johnniwinther): Remove these when we get anonymous local classes.
-typedef void VisitUse<U>(U use);
-
-class WorldImpactVisitorImpl implements WorldImpactVisitor {
-  final VisitUse<StaticUse> _visitStaticUse;
-  final VisitUse<DynamicUse> _visitDynamicUse;
-  final VisitUse<TypeUse> _visitTypeUse;
-
-  WorldImpactVisitorImpl(
-      {VisitUse<StaticUse> visitStaticUse,
-       VisitUse<DynamicUse> visitDynamicUse,
-       VisitUse<TypeUse> visitTypeUse})
-      : _visitStaticUse = visitStaticUse,
-        _visitDynamicUse = visitDynamicUse,
-        _visitTypeUse = visitTypeUse;
-
-  @override
-  void visitStaticUse(StaticUse use) {
-    if (_visitStaticUse != null) {
-      _visitStaticUse(use);
-    }
-  }
-
-  @override
-  void visitDynamicUse(DynamicUse use) {
-    if (_visitDynamicUse != null) {
-      _visitDynamicUse(use);
-    }
-  }
-
-  @override
-  void visitTypeUse(TypeUse use) {
-    if (_visitTypeUse != null) {
-      _visitTypeUse(use);
-    }
-  }
-}
-