Use MOVE_FILE refactoring to implement file rename participant in Editor.

editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/refactoring/ServiceUtils_NEW.java

Index: editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/refactoring/ServiceUtils_NEW.java
diff --git a/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/refactoring/ServiceUtils_NEW.java b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/refactoring/ServiceUtils_NEW.java
index 4dd235a5bd05ba55edde064c13d6a02ce77d39a8..67bfb7c3251f88049e2cf0a6c2260ebac3748747 100644
--- a/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/refactoring/ServiceUtils_NEW.java
+++ b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/refactoring/ServiceUtils_NEW.java
@@ -71,6 +71,27 @@ public class ServiceUtils_NEW {
   }
 
   /**
+   * Simplifies the given {@link Change}. If it is a {@link CompositeChange}, and it is zero
+   * children - returns {@code null}; if it has one child - attempts to simplify it; otherwise
+   * returns the current {@link Change}.
+   */
+  public static Change expandSingleChildCompositeChanges(Change change) {
+    while (change instanceof CompositeChange) {
+      CompositeChange compositeChange = (CompositeChange) change;
+      Change[] children = compositeChange.getChildren();
+      if (children.length == 0) {
+        return null;
+      } else if (children.length == 1) {
+        change = children[0];
+        compositeChange.remove(change);
+      } else {
+        break;
+      }
+    }
+    return change;
+  }
+
+  /**
    * @return the LTK change for the given Services {@link CompositeChange}.
    */
   public static CompositeChange toLTK(SourceChange sourceChange) {