Issue 6836. Using undeclared identifier in static context is now warning.

compiler/java/com/google/dart/compiler/resolver/Elements.java

Index: compiler/java/com/google/dart/compiler/resolver/Elements.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/Elements.java b/compiler/java/com/google/dart/compiler/resolver/Elements.java
index b95d48cd61da7120003192662e85f909a7290c82..a83dfe38bf4298d6e19798ca5a2e615bde830b6b 100644
--- a/compiler/java/com/google/dart/compiler/resolver/Elements.java
+++ b/compiler/java/com/google/dart/compiler/resolver/Elements.java
@@ -766,9 +766,17 @@ static FieldElementImplementation fieldFromNode(DartField node,
         || Elements.isLibrarySource(source, "/core/core.dart");
   }
   
+  public static boolean isCollectionLibrarySource(Source source) {
+    return Elements.isLibrarySource(source, "/collection/collection.dart");
+  }
+  
   public static boolean isHtmlLibrarySource(Source source) {
     return Elements.isLibrarySource(source, "/html/dartium/html_dartium.dart");
   }
+  
+  public static boolean isSourceName(Source source, String requiredName) {
+    return source.getName().equals(requiredName);
+  }
 
   /**
    * @return the {@link LibraryElement} which declares given {@link Element}.