dart2js cps: Clean up and avoid processing unreachable code.

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

Index: pkg/compiler/lib/src/tree_ir/optimization/variable_merger.dart
diff --git a/pkg/compiler/lib/src/tree_ir/optimization/variable_merger.dart b/pkg/compiler/lib/src/tree_ir/optimization/variable_merger.dart
index 91a5aac7d4c6367ae7fa746122cf67d44940a986..fb31f026f4dd6de108936c0e274bf34b08ac508a 100644
--- a/pkg/compiler/lib/src/tree_ir/optimization/variable_merger.dart
+++ b/pkg/compiler/lib/src/tree_ir/optimization/variable_merger.dart
@@ -20,11 +20,6 @@ class VariableMerger extends RecursiveVisitor implements Pass {
     visitStatement(node.body);
   }
 
-  @override
-  void visitInnerFunction(FunctionDefinition node) {
-    rewriteFunction(node);
-  }
-
   /// Rewrites the given function.
   /// This is called for the outermost function and inner functions.
   void rewriteFunction(FunctionDefinition node) {
@@ -112,11 +107,6 @@ class BlockGraphBuilder extends RecursiveVisitor {
     visitStatement(node.body);
   }
 
-  @override
-  void visitInnerFunction(FunctionDefinition node) {
-    // Do nothing. Inner functions are traversed in VariableMerger.
-  }
-
   /// Creates a new block with the current exception handler or [catchBlock]
   /// if provided.
   Block newBlock({Block catchBlock}) {
@@ -506,11 +496,6 @@ class SubstituteVariables extends RecursiveTransformer {
     node.body = visitStatement(node.body);
   }
 
-  @override
-  void visitInnerFunction(FunctionDefinition node) {
-    // Do nothing. Inner functions are traversed in VariableMerger.
-  }
-
   Expression visitVariableUse(VariableUse node) {
     node.variable = replaceRead(node.variable);
     return node;