Redo "Steps towards making dart2js JS AST templates an indepentent library."

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 33 matching lines @@
 
 void main(List<String> arguments) {
   useApi();
   dart2js.main(arguments);
   useConstant(null, null);
   useNode(null);
   useUtil(null);
   useSetlet(null);
   useImmutableEmptySet(null);
   useElementVisitor(new ElementVisitor());
-  useJs(new js.Program(null));
-  useJs(new js.Blob(null));
-  useJs(new js.NamedFunction(null, null));
-  useJs(new js.ArrayHole());
+  useJsNode(new js.Program(null));
+  useJsNode(new js.NamedFunction(null, null));
+  useJsNode(new js.ArrayHole());
+  useJsOther(new js.SimpleJavaScriptPrintingContext());
   useJsBackend(null);
   useConcreteTypesInferrer(null);
   useColor();
   useFilenames();
   useSsa(null);
   useCodeBuffer(null);
   usedByTests();
   useElements(null, null, null, null, null);
   useIr(null, null, null);
   useCompiler(null);
@@ skipping 95 matching lines @@
     ..visitMixinApplicationElement(null)
     ..visitPrefixElement(null)
     ..visitScopeContainerElement(null)
     ..visitTypeDeclarationElement(null)
     ..visitTypeVariableElement(null)
     ..visitTypedefElement(null)
     ..visitVariableElement(null)
     ..visitWarnOnUseElement(null);
 }
 
-useJs(js.Node node) {
+useJsNode(js.Node node) {
   node.asVariableUse();
 }
 
+useJsOther(js.SimpleJavaScriptPrintingContext context) {
+  context.getText();
+}
+
 useJsBackend(js_backend.JavaScriptBackend backend) {
   backend.assembleCode(null);
   backend.annotations.noInlining(null);
   backend.annotations.trustTypeAnnotations(null);
   backend.annotations.assumeDynamic(null);
 }
 
 useConcreteTypesInferrer(concrete_types_inferrer.ConcreteTypesInferrer c) {
   c.debug();
 }
@@ skipping 96 matching lines @@
 }
 
 useScript(dart2jslib.Script script) {
   script.copyWithFile(null);
 }
 
 useProgramBuilder(program_builder.ProgramBuilder builder) {
   builder.buildMethodHackForIncrementalCompilation(null);
   builder.buildFieldsHackForIncrementalCompilation(null);
 }