Remove backends.

compiler/java/com/google/dart/compiler/ast/DartNode.java

Index: compiler/java/com/google/dart/compiler/ast/DartNode.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartNode.java b/compiler/java/com/google/dart/compiler/ast/DartNode.java
index 8c30143c89b5c764112d110e66c2bee22df8d2f6..3761c1f303a8b57a9ced9103743bdfaa6285e383 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartNode.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartNode.java
@@ -18,7 +18,6 @@ import java.util.List;
 public abstract class DartNode extends AbstractNode implements DartVisitable {
 
   private DartNode parent;
-  private boolean isInstrumentedNode;
 
   public final String toSource() {
     DefaultTextOutput out = new DefaultTextOutput(false);
@@ -152,12 +151,4 @@ public abstract class DartNode extends AbstractNode implements DartVisitable {
   public String getObjectIdentifier(){
     return super.toString();
   }
-
-  public boolean isInstrumentedNode() {
-    return isInstrumentedNode;
-  }
-
-  public void setInstrumentedNode(boolean isInstrumentedNode) {
-    this.isInstrumentedNode = isInstrumentedNode;
-  }
 }