Set up a stub pipline for using the new cps-based ir to generate js.

pkg/compiler/lib/src/cps_ir/cps_ir_builder_visitor.dart

Index: pkg/compiler/lib/src/cps_ir/cps_ir_builder_visitor.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_builder_visitor.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_builder_visitor.dart
index b7ac48ed878caffb5d9ab201c12dc28fb7209306..69581d69697d4fdf4fc16032c9007ae06e8b7f44 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_builder_visitor.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_builder_visitor.dart
@@ -33,27 +33,33 @@ class IrBuilderTask extends CompilerTask {
 
   ir.FunctionDefinition getIr(Element element) => nodes[element.implementation];
 
+  ir.FunctionDefinition buildNode(AstElement element) {
+    if (!canBuild(element)) return null;
+    TreeElements elementsMapping = element.resolvedAst.elements;
+    element = element.implementation;
+    return compiler.withCurrentElement(element, () {
+      SourceFile sourceFile = elementSourceFile(element);
+      IrBuilderVisitor builder =
+          new IrBuilderVisitor(elementsMapping, compiler, sourceFile);
+      ir.FunctionDefinition function;
+      function = builder.buildFunction(element);
+
+      if (function != null) {
+        compiler.tracer.traceCompilation(element.name, null);
+        compiler.tracer.traceGraph("IR Builder", function);
+      }
+      return function;
+    });
+  }
+
   void buildNodes({bool useNewBackend: false}) {
     if (!irEnabled(useNewBackend: useNewBackend)) return;

[floitsch, 2014/11/12 11:03:19]

Why does the builder need to know about backends?
It looks to me like this should have been checked before.

[sigurdm, 2014/11/13 08:29:41]

I agree - I removed it - it was only used from tests.

     measure(() {
       Set<Element> resolved = compiler.enqueuer.resolution.resolvedElements;
       resolved.forEach((AstElement element) {
-        if (canBuild(element)) {
-          TreeElements elementsMapping = element.resolvedAst.elements;
-          element = element.implementation;
-          compiler.withCurrentElement(element, () {
-            SourceFile sourceFile = elementSourceFile(element);
-            IrBuilderVisitor builder =
-                new IrBuilderVisitor(elementsMapping, compiler, sourceFile);
-            ir.FunctionDefinition function;
-            function = builder.buildFunction(element);
-
-            if (function != null) {
-              nodes[element] = function;
-              compiler.tracer.traceCompilation(element.name, null);
-              compiler.tracer.traceGraph("IR Builder", function);
-            }
-          });
+        ir.FunctionDefinition functionDefinition = buildNode(element);
+        if (functionDefinition != null) {
+          nodes[element] = functionDefinition;
         }
       });
     });