dart2js cps: Clean up and avoid processing unreachable code.

pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart

Index: pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
diff --git a/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart b/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
index 1da49af039387e30978d8090a34f6f356b69ca4d..6667ded4b3ab0deedd68bd3f0dde4a7720c4ebee 100644
--- a/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
+++ b/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
@@ -579,11 +579,6 @@ class StatementRewriter extends Transformer implements Pass {
     return node;
   }
 
-  Expression visitFunctionExpression(FunctionExpression node) {
-    new StatementRewriter.nested(this).rewrite(node.definition);
-    return node;
-  }
-
   Statement visitReturn(Return node) {
     node.value = visitExpression(node.value);
     return node;
@@ -1256,8 +1251,6 @@ class IsVariableUsedVisitor extends RecursiveVisitor {
       wasFound = true;
     }
   }
-
-  visitInnerFunction(FunctionDefinition node) {}
 }
 
 typedef VariableUseCallback(VariableUse use);
@@ -1269,8 +1262,6 @@ class VariableUseVisitor extends RecursiveVisitor {
 
   visitVariableUse(VariableUse use) => callback(use);
 
-  visitInnerFunction(FunctionDefinition node) {}
-
   static void visit(Expression node, VariableUseCallback callback) {
     new VariableUseVisitor(callback).visitExpression(node);
   }