Add MultiSourceInformationStrategy

pkg/compiler/lib/src/js/js.dart

 // Copyright (c) 2015, 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.
 
 library js;
 
 import 'package:js_ast/js_ast.dart';
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
@@ skipping 26 matching lines @@
     Renamer renamerForNames: JavaScriptPrintingOptions.identityRenamer}) {
   JavaScriptSourceInformationStrategy sourceInformationFactory =
       compiler.backend.sourceInformationStrategy;
   JavaScriptPrintingOptions options = new JavaScriptPrintingOptions(
       shouldCompressOutput: compiler.options.enableMinification,
       minifyLocalVariables: allowVariableMinification,
       preferSemicolonToNewlineInMinifiedOutput: USE_LAZY_EMITTER,
       renamerForNames: renamerForNames);
   CodeBuffer outBuffer = new CodeBuffer();
   SourceInformationProcessor sourceInformationProcessor =
-      sourceInformationFactory
-          .createProcessor(new SourceLocationsMapper(outBuffer));
+      sourceInformationFactory.createProcessor(
+          new SourceMapperProviderImpl(outBuffer),
+          const SourceInformationReader());
   Dart2JSJavaScriptPrintingContext context =
       new Dart2JSJavaScriptPrintingContext(
           compiler.reporter, monitor, outBuffer, sourceInformationProcessor);
   Printer printer = new Printer(options, context);
   printer.visit(node);
   sourceInformationProcessor.process(node, outBuffer);
   return outBuffer;
 }
 
 class Dart2JSJavaScriptPrintingContext implements JavaScriptPrintingContext {
@@ skipping 129 matching lines @@
   }
   if (node is PropertyAccess) {
     PropertyAccess access = node;
     if (access.receiver is InterpolatedExpression) {
       InterpolatedExpression hole = access.receiver;
       return hole.isPositional && hole.nameOrPosition == 0;
     }
   }
   return false;
 }