Create and test source mapping for invocations.

pkg/compiler/lib/src/js_backend/codegen/task.dart

Index: pkg/compiler/lib/src/js_backend/codegen/task.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/task.dart b/pkg/compiler/lib/src/js_backend/codegen/task.dart
index 93fe011ff425145658aa8d71b0fdca8fb7960f24..35f17592f45b55bdae2afe192017f77fe347dd60 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/task.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/task.dart
@@ -20,7 +20,7 @@ import '../../types/types.dart' show TypeMask, UnionTypeMask, FlatTypeMask,
     ForwardingTypeMask;
 import '../../elements/elements.dart';
 import '../../js/js.dart' as js;
-import '../../io/source_information.dart' show SourceInformationFactory;
+import '../../io/source_information.dart' show SourceInformationStrategy;
 import '../../tree_ir/tree_ir_builder.dart' as tree_builder;
 import '../../cps_ir/optimizers.dart';
 import '../../cps_ir/optimizers.dart' as cps_opt;
@@ -37,7 +37,7 @@ class CpsFunctionCompiler implements FunctionCompiler {
   final ConstantSystem constantSystem;
   final Compiler compiler;
   final Glue glue;
-  final SourceInformationFactory sourceInformationFactory;
+  final SourceInformationStrategy sourceInformationFactory;
 
   // TODO(karlklose,sigurm): remove and update dart-doc of [compile].
   final FunctionCompiler fallbackCompiler;
@@ -47,7 +47,7 @@ class CpsFunctionCompiler implements FunctionCompiler {
   IrBuilderTask get irBuilderTask => compiler.irBuilder;
 
   CpsFunctionCompiler(Compiler compiler, JavaScriptBackend backend,
-                      SourceInformationFactory sourceInformationFactory)
+                      SourceInformationStrategy sourceInformationFactory)
       : fallbackCompiler =
             new ssa.SsaFunctionCompiler(backend, sourceInformationFactory),
         this.sourceInformationFactory = sourceInformationFactory,
@@ -216,7 +216,7 @@ class CpsFunctionCompiler implements FunctionCompiler {
 
   js.Node attachPosition(js.Node node, AstElement element) {
     return node.withSourceInformation(
-        sourceInformationFactory.forContext(element)
+        sourceInformationFactory.createBuilderForContext(element)
             .buildDeclaration(element));
   }
 }