Make CompilerTask independent of compiler.

pkg/compiler/lib/src/js_emitter/code_emitter_task.dart

Index: pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
diff --git a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
index 28583fcbeaf5eedc6a77e86e22d7c656126f264d..da0aff8169af40929bf99e2e313fc78799d66244 100644
--- a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
+++ b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
@@ -19,6 +19,7 @@ class CodeEmitterTask extends CompilerTask {
   NativeEmitter nativeEmitter;
   MetadataCollector metadataCollector;
   Emitter emitter;
+  final Compiler compiler;
 
   /// Records if a type variable is read dynamically for type tests.
   final Set<TypeVariableElement> readTypeVariables =
@@ -35,9 +36,10 @@ class CodeEmitterTask extends CompilerTask {
 
   CodeEmitterTask(Compiler compiler, Namer namer, bool generateSourceMap,
       bool useStartupEmitter)
-      : super(compiler),
+      : compiler = compiler,
         this.namer = namer,
-        this.typeTestRegistry = new TypeTestRegistry(compiler) {
+        this.typeTestRegistry = new TypeTestRegistry(compiler),
+        super(compiler.measurer) {
     nativeEmitter = new NativeEmitter(this);
     if (USE_LAZY_EMITTER) {
       emitter = new lazy_js_emitter.Emitter(compiler, namer, nativeEmitter);