Refactor SourceMapBuilder to allow for post-processing.

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;
 
 import '../compiler.dart' as api;
 
 import 'colors.dart' as colors;
 import 'constants/constant_system.dart' as constants;
 import 'constants/values.dart' as constants;
 import 'cps_ir/cps_ir_builder.dart' as ir_builder;
 import 'cps_ir/cps_ir_builder_task.dart' as ir_builder;
 import 'cps_ir/cps_ir_nodes_sexpr.dart' as cps_ir_nodes_sexpr;
 import 'tree_ir/tree_ir_nodes.dart' as tree_ir;
 import 'dart_types.dart' as dart_types;
 import 'dart2js.dart' as dart2js;
 import 'dart2jslib.dart' as dart2jslib;
 import 'elements/elements.dart' as elements;
 import 'elements/modelx.dart' as modelx;
 import 'elements/visitor.dart' as elements_visitor;
 import 'filenames.dart' as filenames;
 import 'inferrer/concrete_types_inferrer.dart' as concrete_types_inferrer;
 import 'inferrer/type_graph_inferrer.dart' as type_graph_inferrer;
 import 'io/code_output.dart' as io;
+import 'io/source_map_builder.dart' as io;
 import 'js/js.dart' as js;
 import 'js_backend/js_backend.dart' as js_backend;
 import 'js_emitter/js_emitter.dart' as js_emitter;
 import 'js_emitter/program_builder.dart' as program_builder;
 import 'resolution/semantic_visitor.dart' as semantic_visitor;
 import 'source_file_provider.dart' as source_file_provider;
 import 'ssa/ssa.dart' as ssa;
 import 'tree/tree.dart' as tree;
 import 'universe/universe.dart' as universe;
 import 'util/util.dart' as util;
@@ skipping 18 matching lines @@
   useElementVisitor(new ElementVisitor());
   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);
+  useIo(null, null);
   usedByTests();
   useElements(null, null, null, null, null);
   useIr(null, null);
   useCompiler(null);
   useTypes();
   useCodeEmitterTask(null);
   useScript(null);
   useProgramBuilder(null);
   useSemanticVisitor();
   useTreeVisitors();
@@ skipping 126 matching lines @@
 useFilenames() {
   filenames.appendSlash(null);
 }
 
 useSsa(ssa.HInstruction instruction) {
   instruction.isConstantNumber();
   new ssa.HAndOrBlockInformation(null, null, null);
   new ssa.HStatementSequenceInformation(null);
 }
 
-useCodeBuffer(io.CodeBuffer buffer) {
+useIo(io.CodeBuffer buffer, io.LineColumnMap map) {
+  map..addFirst(null, null, null)
+     ..forEachLine(null)
+     ..getFirstElementsInLine(null)
+     ..forEachColumn(null, null);
 }
 
 usedByTests() {
   // TODO(ahe): We should try to avoid including API used only for tests. In
   // most cases, such API can be moved to a test library.
   dart2jslib.World world = null;
   dart2jslib.Compiler compiler = null;
   compiler.currentlyInUserCode();
   type_graph_inferrer.TypeGraphInferrer typeGraphInferrer = null;
   source_file_provider.SourceFileProvider sourceFileProvider = null;
@@ skipping 75 matching lines @@
   visitFieldDefinition(tree_ir.FieldDefinition node) {}
 
   visitFieldInitializer(tree_ir.FieldInitializer node) {}
   visitSuperInitializer(tree_ir.SuperInitializer node) {}
 }
 
 useTreeVisitors() {
   new DummyTreeVisitor().visitRootNode(null);
   new DummyTreeVisitor().visitInitializer(null);
 }