dart2js: remove additionalProperties and store it directly as nativeBlob.

pkg/compiler/lib/src/js_emitter/program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/program_builder.dart b/pkg/compiler/lib/src/js_emitter/program_builder.dart
index 15f10318e63494e52aa23dafeacc8c094b57da96..5b35217ce4b63c2959a8933e4db29f9afc7afc9e 100644
--- a/pkg/compiler/lib/src/js_emitter/program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/program_builder.dart
@@ -99,13 +99,8 @@ class ProgramBuilder {
         .map((ClassElement classElement) => _classes[classElement])
         .toList();
 
-    Map<Class, Map<String, js.Expression>> additionalProperties =
-        new Map<Class, Map<String, js.Expression>>();
-
     _unneededNativeClasses =
-        _task.nativeEmitter.prepareNativeClasses(
-            nativeClasses,
-            additionalProperties);
+        _task.nativeEmitter.prepareNativeClasses(nativeClasses);
 
     MainFragment mainOutput = _buildMainOutput(_registry.mainLibrariesMap);
     Iterable<Fragment> deferredOutputs = _registry.deferredLibrariesMap
@@ -122,7 +117,6 @@ class ProgramBuilder {
 
     return new Program(
         outputs,
-        additionalProperties,
         _buildLoadMap(),
         outputContainsNativeClasses: containsNativeClasses,
         outputContainsConstantList: _task.outputContainsConstantList);