cps_ir: Clean up BuilderTask.

pkg/compiler/lib/src/use_unused_api.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// This file use methods that aren't used by dart2js.dart, but that we wish to
 /// keep anyway. This might be general API that isn't currently in use,
 /// debugging aids, or API only used for testing (see TODO below).
 
 library dart2js.use_unused_api;
 
@@ skipping 51 matching lines @@
   useJsNode(new js.ArrayHole());
   useJsOther(new js.SimpleJavaScriptPrintingContext());
   useJsBackend(null);
   useConcreteTypesInferrer(null);
   useColor();
   useFilenames();
   useSsa(null);
   useIo(null, null);
   usedByTests();
   useElements();
-  useIr(null, null);
+  useIr(null);
   useCompiler(null);
   useTypes();
   useCodeEmitterTask(null);
   useScript(null);
   useProgramBuilder(null);
   useSemanticVisitor();
   useTreeVisitors();
 }
 
 useApi() {
@@ skipping 170 matching lines @@
      elements.LibraryElement l]) {
   e.lookupClassMember(null);
   e.lookupInterfaceMember(null);
   n.isAccessibleFrom(null);
   f.reuseElement();
   pce.copyWithEnclosing(null);
   pfe.copyWithEnclosing(null);
   l.forEachImport(null);
 }
 
-useIr(ir_builder.IrBuilderTask task,
-      ir_builder.IrBuilder builder) {
-  task
-    ..hasIr(null)
-    ..getIr(null);
+useIr(ir_builder.IrBuilder builder) {
   builder
     ..buildStringConstant(null)
     ..buildDynamicGet(null, null);
 }
 
 useCompiler(dart2jslib.Compiler compiler) {
   compiler.libraryLoader
       ..reset()
       ..resetAsync(null)
       ..lookupLibrary(null);
@@ skipping 28 matching lines @@
 
 class TreeVisitor1 extends tree_ir.ExpressionVisitor1
                       with tree_ir.StatementVisitor1 {
   noSuchMethod(inv) {}
 }
 
 useTreeVisitors() {
   new TreeVisitor1().visitExpression(null, null);
   new TreeVisitor1().visitStatement(null, null);
 }