Fix source information positions for deserialized patched elements.

pkg/compiler/lib/src/ssa/codegen.dart

Index: pkg/compiler/lib/src/ssa/codegen.dart
diff --git a/pkg/compiler/lib/src/ssa/codegen.dart b/pkg/compiler/lib/src/ssa/codegen.dart
index 5938e1c36f1e13b63a9ce7c9fb1b24b11fc1d10e..8b9ab1691158179b1b3461361c14bd0d79f67fea 100644
--- a/pkg/compiler/lib/src/ssa/codegen.dart
+++ b/pkg/compiler/lib/src/ssa/codegen.dart
@@ -51,7 +51,7 @@ class SsaCodeGeneratorTask extends CompilerTask {
 
     return new js.Fun(parameters, body, asyncModifier: asyncModifier)
         .withSourceInformation(sourceInformationFactory
-            .createBuilderForContext(resolvedAst.element)
+            .createBuilderForContext(resolvedAst)
             .buildDeclaration(resolvedAst));
   }
 
@@ -67,7 +67,7 @@ class SsaCodeGeneratorTask extends CompilerTask {
     return measure(() {
       compiler.tracer.traceGraph("codegen", graph);
       SourceInformation sourceInformation = sourceInformationFactory
-          .createBuilderForContext(work.element)
+          .createBuilderForContext(work.resolvedAst)
           .buildDeclaration(work.resolvedAst);
       SsaCodeGenerator codegen = new SsaCodeGenerator(backend, work);
       codegen.visitGraph(graph);