Revert "Remove JavaScriptBackend from ClosedWorldBase"

pkg/compiler/lib/src/compiler.dart

Index: pkg/compiler/lib/src/compiler.dart
diff --git a/pkg/compiler/lib/src/compiler.dart b/pkg/compiler/lib/src/compiler.dart
index 13443a32c58013977045d93ba84c3ff997dc75b2..65620fda8e12fd01ac36f67a8728c26b339a147f 100644
--- a/pkg/compiler/lib/src/compiler.dart
+++ b/pkg/compiler/lib/src/compiler.dart
@@ -626,7 +626,6 @@ abstract class Compiler {
 
         processQueue(resolutionEnqueuer, mainMethod, libraryLoader.libraries,
             onProgress: showResolutionProgress);
-        backend.onResolutionEnd();
         resolutionEnqueuer.logSummary(reporter.log);
 
         _reporter.reportSuppressedMessagesSummary();
@@ -705,10 +704,10 @@ abstract class Compiler {
   ClosedWorldRefiner closeResolution() {
     phase = PHASE_DONE_RESOLVING;
 
-    ClosedWorldImpl world = resolutionWorldBuilder.closeWorld();
+    ClosedWorldImpl world = resolutionWorldBuilder.closeWorld(reporter);
     // Compute whole-program-knowledge that the backend needs. (This might
     // require the information computed in [world.closeWorld].)
-    backend.onResolutionClosedWorld(world, world);
+    backend.onResolutionComplete(world, world);
 
     deferredLoadTask.onResolutionComplete(mainFunction);