Fix warnings.

lib/compiler/implementation/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.
 
 typedef void Recompile(Element element);
 
 class ReturnInfo {
   HType returnType;
   List<Element> compiledFunctions;
 
@@ skipping 21 matching lines @@
   }
 
   addCompiledFunction(FunctionElement function) =>
       compiledFunctions.add(function);
 }
 
 class HTypeList {
   final List<HType> types;
 
   HTypeList(int length) : types = new List<HType>(length);
-  const HTypeList.allUnknown() : types = null;
+  const HTypeList.withAllUnknown() : types = null;
 
   factory HTypeList.fromInvocation(HInvoke node, HTypeMap types) {
     bool allUnknown = true;
     for (int i = 1; i < node.inputs.length; i++) {
       if (types[node.inputs[i]] != HType.UNKNOWN) {
         allUnknown = false;
         break;
       }
     }
     if (allUnknown) return HTypeList.ALL_UNKNOWN;
 
     HTypeList result = new HTypeList(node.inputs.length - 1);
     for (int i = 0; i < result.types.length; i++) {
       result.types[i] = types[node.inputs[i + 1]];
     }
     return result;
   }
 
-  static const HTypeList ALL_UNKNOWN = const HTypeList.allUnknown();
+  static const HTypeList ALL_UNKNOWN = const HTypeList.withAllUnknown();
 
   bool get allUnknown => types === null;
   int get length => types.length;
   HType operator[](int index) => types[index];
 
   HTypeList union(HTypeList other) {
     if (allUnknown) return this;
     if (other.allUnknown) return other;
     if (length != other.length) return HTypeList.ALL_UNKNOWN;
     bool onlyUnknown = true;
@@ skipping 505 matching lines @@
           return const SourceString('listSuperTypeCheck');
         }
       } else if (nativeCheck) {
         return const SourceString('callTypeCheck');
       } else {
         return const SourceString('propertyTypeCheck');
       }
     }
   }
 }