dart2js: keep track of non-final static fields.

pkg/compiler/lib/src/js_emitter/code_emitter_task.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 dart2js.js_emitter;
 
 const USE_NEW_EMITTER = const bool.fromEnvironment("dart2js.use.new.emitter");
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
  * in classes) are ignored, since they can be treated as non-class elements.
  *
- * The code for the containing (used) methods must exist in the [:universe:].
+ * The code for the containing (used) methods must exist in the `universe`.
  */
 class CodeEmitterTask extends CompilerTask {
   // TODO(floitsch): the code-emitter task should not need a namer.
   final Namer namer;
   final TypeTestRegistry typeTestRegistry;
   NativeEmitter nativeEmitter;
   MetadataCollector metadataCollector;
   OldEmitter oldEmitter;
   Emitter emitter;
 
@@ skipping 332 matching lines @@
     for (Element element in Elements.sortedByPosition(elements)) {
       List<Element> list = outputStaticLists.putIfAbsent(
           compiler.deferredLoadTask.outputUnitForElement(element),
           () => new List<Element>());
       list.add(element);
     }
   }
 
   void computeNeededStaticNonFinalFields() {
     JavaScriptConstantCompiler handler = backend.constants;
-    Iterable<VariableElement> staticNonFinalFields =
-        handler.getStaticNonFinalFieldsForEmission();
+    Iterable<VariableElement> staticNonFinalFields = handler
+        .getStaticNonFinalFieldsForEmission()
+        .where(compiler.codegenWorld.allReferencedStaticFields.contains);
     for (Element element in Elements.sortedByPosition(staticNonFinalFields)) {
       List<VariableElement> list = outputStaticNonFinalFieldLists.putIfAbsent(
             compiler.deferredLoadTask.outputUnitForElement(element),
             () => new List<VariableElement>());
       list.add(element);
     }
   }
 
   void computeNeededLibraries() {
     void addSurroundingLibraryToSet(Element element) {
@@ skipping 74 matching lines @@
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   /// Returns the JS code for accessing the given [constant].
   jsAst.Expression constantReference(ConstantValue constant);
 
   /// Returns the JS template for the given [builtin].
   jsAst.Template templateForBuiltin(JsBuiltin builtin);
 
   void invalidateCaches();
 }