Remove printDebugInfo from Unparser

lib/compiler/implementation/tree/unparser.dart

Index: lib/compiler/implementation/tree/unparser.dart
diff --git a/lib/compiler/implementation/tree/unparser.dart b/lib/compiler/implementation/tree/unparser.dart
index cf0911d10f4728d673d6c54d0471de76a8640fd3..a00b514b20057419f211e8e334a3591eebdfabac 100644
--- a/lib/compiler/implementation/tree/unparser.dart
+++ b/lib/compiler/implementation/tree/unparser.dart
@@ -4,9 +4,8 @@
 
 class Unparser implements Visitor {
   StringBuffer sb;
-  final bool printDebugInfo;
 
-  Unparser([this.printDebugInfo = false]);
+  Unparser();
 
   String unparse(Node node) {
     sb = new StringBuffer();
@@ -19,13 +18,7 @@ class Unparser implements Visitor {
   }
 
   visit(Node node) {
-    if (node !== null) {
-      if (printDebugInfo) sb.add('[${node.getObjectDescription()}: ');
-      node.accept(this);
-      if (printDebugInfo) sb.add(']');
-    } else if (printDebugInfo) {
-      sb.add('[null]');
-    }
+    if (node !== null) node.accept(this);
   }
 
   visitBlock(Block node) {