Reapply "Add "load from .dill" file capability and run a white-box test.""

pkg/compiler/tool/perf.dart

Index: pkg/compiler/tool/perf.dart
diff --git a/pkg/compiler/tool/perf.dart b/pkg/compiler/tool/perf.dart
index a9c8e6f02dd384a8787ad51d6b5ab4d0e4e6b250..3a61123955285fd896adf49a85c97f1f519c16b9 100644
--- a/pkg/compiler/tool/perf.dart
+++ b/pkg/compiler/tool/perf.dart
@@ -11,7 +11,7 @@ import 'dart:io';
 import 'package:compiler/compiler_new.dart';
 import 'package:compiler/src/apiimpl.dart';
 import 'package:compiler/src/compiler.dart';
-import 'package:compiler/src/elements/elements.dart';
+import 'package:compiler/src/elements/entities.dart' show LibraryEntity;
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/diagnostics/diagnostic_listener.dart';
 import 'package:compiler/src/diagnostics/messages.dart'
@@ -361,7 +361,7 @@ class MyCompiler extends CompilerImpl {
         resolutionEnqueuer.applyImpact(mainImpact);
         // Note: we enqueue everything in the program so we measure generating
         // kernel for the entire code, not just what's reachable from main.
-        libraryLoader.libraries.forEach((LibraryElement library) {
+        libraryLoader.libraries.forEach((LibraryEntity library) {
           resolutionEnqueuer.applyImpact(computeImpactForLibrary(library));
         });