Finish strong mode cleaning of dart2js.

pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart

Index: pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart b/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
index 33e986a35e7b3e150d9ab12f0aeb3841a3cbc2d7..19af31f3f9bc6114ca1677d8050beea8dd77d9af 100644
--- a/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
@@ -1065,7 +1065,7 @@ class Emitter extends js_emitter.EmitterBase {
 
   jsAst.Expression generateLibraryDescriptor(
       LibraryEntity library, Fragment fragment) {
-    var uri = "";
+    dynamic uri = "";
     if (!compiler.options.enableMinification ||
         backend.mirrorsData.mustPreserveUris) {
       uri = library.canonicalUri;
@@ -1628,7 +1628,7 @@ class Emitter extends js_emitter.EmitterBase {
     deferredParts.forEach(counter.countTokens);
     task.metadataCollector.finalizeTokens();
     if (backend.namer is jsAst.TokenFinalizer) {
-      var finalizer = backend.namer;
+      dynamic finalizer = backend.namer;
       finalizer.finalizeTokens();
     }
   }