Remove AbstractVisitor.

dart/lib/compiler/implementation/ssa/builder.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.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 3995 matching lines @@
   }
 }
 
 /**
  * Visitor that handles generation of string literals (LiteralString,
  * StringInterpolation), and otherwise delegates to the given visitor for
  * non-literal subexpressions.
  * TODO(lrn): Consider whether to handle compile time constant int/boolean
  * expressions as well.
  */
-class StringBuilderVisitor extends AbstractVisitor {
+class StringBuilderVisitor extends Visitor {
   final SsaBuilder builder;
   final Node diagnosticNode;
 
   /**
    * The string value generated so far.
    */
   HInstruction result = null;
 
   StringBuilderVisitor(this.builder, this.diagnosticNode);
 
@@ skipping 32 matching lines @@
     HInstruction instruction = new HStringConcat(left, right, diagnosticNode);
     builder.add(instruction);
     return instruction;
   }
 }
 
 /**
  * This class visits the method that is a candidate for inlining and
  * finds whether it is too difficult to inline.
  */
-class InlineWeeder extends AbstractVisitor {
+class InlineWeeder extends Visitor {
   final TreeElements elements;
   bool seenReturn = false;
   bool tooDifficult = false;
 
   InlineWeeder(this.elements);
 
   static bool canBeInlined(FunctionExpression functionExpression,
                            TreeElements elements) {
     InlineWeeder weeder = new InlineWeeder(elements);
     weeder.visit(functionExpression.body);
@@ skipping 298 matching lines @@
           new HSubGraphBlockInformation(elseBranch.graph));
 
     HBasicBlock conditionStartBlock = conditionBranch.block;
     conditionStartBlock.setBlockFlow(info, joinBlock);
     SubGraph conditionGraph = conditionBranch.graph;
     HIf branch = conditionGraph.end.last;
     assert(branch is HIf);
     branch.blockInformation = conditionStartBlock.blockFlow;
   }
 }