Switch Js to JS

pkg/compiler/lib/src/js_backend/backend.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_backend;
 
 const VERBOSE_OPTIMIZER_HINTS = false;
 
 class JavaScriptItemCompilationContext extends ItemCompilationContext {
   final Set<HInstruction> boundsChecked = new Set<HInstruction>();
@@ skipping 2047 matching lines @@
         jsGetNameEnum = find(library, 'JsGetName');
         jsBuiltinEnum = find(library, 'JsBuiltin');
       } else if (uri == Uris.dart_html) {
         htmlLibraryIsLoaded = true;
       } else if (uri == PACKAGE_LOOKUP_MAP) {
         lookupMapAnalysis.init(library);
       } else if (uri == Uris.dart__native_typed_data) {
         typedArrayClass = findClass('NativeTypedArray');
         typedArrayOfIntClass = findClass('NativeTypedArrayOfInt');
       } else if (uri == PACKAGE_JS) {
-        jsAnnotationClass = find(library, 'Js');
+        jsAnnotationClass = find(library, 'JS');
       }
       annotations.onLibraryScanned(library);
     });
   }
 
   Future onLibrariesLoaded(LoadedLibraries loadedLibraries) {
     if (!loadedLibraries.containsLibrary(Uris.dart_core)) {
       return new Future.value();
     }
 
@@ skipping 954 matching lines @@
 }
 
 /// Records that [constant] is used by the element behind [registry].
 class Dependency {
   final ConstantValue constant;
   final Element annotatedElement;
 
   const Dependency(this.constant, this.annotatedElement);
 }