Use entities in impact transformers.

pkg/compiler/lib/src/js_backend/runtime_types.dart

Index: pkg/compiler/lib/src/js_backend/runtime_types.dart
diff --git a/pkg/compiler/lib/src/js_backend/runtime_types.dart b/pkg/compiler/lib/src/js_backend/runtime_types.dart
index 677fbb783fb5e718c0d6eaaa37e281b2afca626f..3101e8d617b8045e74e18b75ac7a311bf68b2a7c 100644
--- a/pkg/compiler/lib/src/js_backend/runtime_types.dart
+++ b/pkg/compiler/lib/src/js_backend/runtime_types.dart
@@ -29,7 +29,7 @@ abstract class RuntimeTypesNeed {
 /// Interface for computing classes and methods that need runtime types.
 abstract class RuntimeTypesNeedBuilder {
   /// Registers that [cls] contains a type variable literal.
-  void registerClassUsingTypeVariableExpression(ClassElement cls);
+  void registerClassUsingTypeVariableExpression(ClassEntity cls);
 
   /// Registers that if [element] needs reified runtime type information then so
   /// does [dependency].
@@ -44,7 +44,7 @@ abstract class RuntimeTypesNeedBuilder {
   ///
   /// Here `A` need reified runtime type information because `B` needs it in
   /// order to generate the check against `B<int>`.
-  void registerRtiDependency(ClassElement element, ClassElement dependency);
+  void registerRtiDependency(ClassEntity element, ClassEntity dependency);
 
   /// Computes the [RuntimeTypesNeed] for the data registered with this builder.
   RuntimeTypesNeed computeRuntimeTypesNeed(