Remove JavaScriptBackend from ClosedWorldBase

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

Index: pkg/compiler/lib/src/js_backend/backend.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend.dart b/pkg/compiler/lib/src/js_backend/backend.dart
index 6dd3a73a9eabc50d425c74a15948ea30c3eaeb49..c4504d6da210d0de005a109ae0f3182e48525b0f 100644
--- a/pkg/compiler/lib/src/js_backend/backend.dart
+++ b/pkg/compiler/lib/src/js_backend/backend.dart
@@ -750,6 +750,7 @@ class JavaScriptBackend {
     });
   }
 
+  /// Called before processing of the resolution queue is started.
   void onResolutionStart(ResolutionEnqueuer enqueuer) {
     // TODO(johnniwinther): Avoid the compiler.elementEnvironment.getThisType
     // calls. Currently needed to ensure resolution of the classes for various
@@ -764,7 +765,14 @@ class JavaScriptBackend {
     validateInterceptorImplementsAllObjectMethods(commonElements.jsNullClass);
   }
 
-  void onResolutionComplete(
+  /// Called when the resolution queue has been closed.
+  void onResolutionEnd() {
+    _backendUsage = backendUsageBuilder.close();
+    _interceptorData = interceptorDataBuilder.onResolutionComplete();
+  }
+
+  /// Called when the closed world from resolution has been computed.
+  void onResolutionClosedWorld(
       ClosedWorld closedWorld, ClosedWorldRefiner closedWorldRefiner) {
     for (MemberEntity entity
         in compiler.enqueuer.resolution.processedEntities) {
@@ -772,7 +780,6 @@ class JavaScriptBackend {
     }
     mirrorsDataBuilder.computeMembersNeededForReflection(
         compiler.enqueuer.resolution.worldBuilder, closedWorld);
-    _backendUsage = backendUsageBuilder.close();
     _rtiNeed = rtiNeedBuilder.computeRuntimeTypesNeed(
         compiler.enqueuer.resolution.worldBuilder,
         closedWorld,
@@ -780,7 +787,6 @@ class JavaScriptBackend {
         commonElements,
         _backendUsage,
         enableTypeAssertions: compiler.options.enableTypeAssertions);
-    _interceptorData = interceptorDataBuilder.onResolutionComplete(closedWorld);
     _oneShotInterceptorData =
         new OneShotInterceptorData(interceptorData, commonElements);
     mirrorsResolutionAnalysis.onResolutionComplete();