dart2js: Remove oldEmitter field in emitter-task.

pkg/compiler/lib/src/dump_info.dart

Index: pkg/compiler/lib/src/dump_info.dart
diff --git a/pkg/compiler/lib/src/dump_info.dart b/pkg/compiler/lib/src/dump_info.dart
index 3e4cda2c9d38e231d9438ef524cdabfcf521237f..5ec5998270cd59c0e3cb593fd0a7a470ceae4475 100644
--- a/pkg/compiler/lib/src/dump_info.dart
+++ b/pkg/compiler/lib/src/dump_info.dart
@@ -21,6 +21,7 @@ import 'dart2jslib.dart' show
 import 'types/types.dart' show TypeMask;
 import 'deferred_load.dart' show OutputUnit;
 import 'js_backend/js_backend.dart' show JavaScriptBackend;
+import 'js_emitter/js_emitter.dart' show OldEmitter;
 import 'js/js.dart' as jsAst;
 import 'universe/universe.dart' show Selector, UniverseSelector;
 import 'util/util.dart' show NO_LOCATION_SPANNABLE;
@@ -596,6 +597,9 @@ class DumpInfoTask extends CompilerTask {
         new List<Map<String, dynamic>>();
 
     JavaScriptBackend backend = compiler.backend;
+    // Dump-info currently only works with the full emitter. If another
+    // emitter is used it will fail here.
+    OldEmitter fullEmitter = backend.emitter.emitter;
 
     for (OutputUnit outputUnit in
         infoCollector.mapper._outputUnit._elementToId.keys) {
@@ -603,7 +607,7 @@ class DumpInfoTask extends CompilerTask {
       outputUnits.add(<String, dynamic> {
         'id': id,
         'name': outputUnit.name,
-        'size': backend.emitter.oldEmitter.outputBuffers[outputUnit].length,
+        'size': fullEmitter.outputBuffers[outputUnit].length,
       });
     }