Remove code supporting incremental compilation in dart2js

pkg/compiler/lib/src/common/resolution.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.
 
 library dart2js.common.resolution;
 
 import '../common.dart';
 import '../compile_time_constants.dart';
 import '../constants/expressions.dart' show ConstantExpression;
 import '../constants/values.dart' show ConstantValue;
@@ skipping 187 matching lines @@
 
   /// Removes the [WorldImpact] for [element] from the resolution cache. Later
   /// calls to [getWorldImpact] or [computeWorldImpact] returns an empty impact.
   void uncacheWorldImpact(Element element);
 
   /// Removes the [WorldImpact]s for all [Element]s in the resolution cache. ,
   /// Later calls to [getWorldImpact] or [computeWorldImpact] returns an empty
   /// impact.
   void emptyCache();
 
-  void forgetElement(Element element);
-
   /// Returns `true` if [value] is the top-level [proxy] annotation from the
   /// core library.
   bool isProxyConstant(ConstantValue value);
 }
 
 /// A container of commonly used dependencies for tasks that involve parsing.
 abstract class ParsingContext {
   factory ParsingContext(DiagnosticReporter reporter, ParserTask parser,
       PatchParserTask patchParser, Backend backend) = _ParsingContext;
 
@@ skipping 30 matching lines @@
       if (cls.isPatch) {
         patchParser.parsePatchClassNode(cls);
       }
     });
   }
 
   @override
   ScannerOptions getScannerOptionsFor(Element element) => new ScannerOptions(
       canUseNative: backend.canLibraryUseNative(element.library));
 }