Further work on 17522

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/utilities/ast/DeferredLibraryReferenceDetector.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/utilities/ast/DeferredLibraryReferenceDetector.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/utilities/ast/DeferredLibraryReferenceDetector.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/utilities/ast/DeferredLibraryReferenceDetector.java
new file mode 100644
index 0000000000000000000000000000000000000000..0e6201c5bbfb2180160140c03850000236021842
--- /dev/null
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/utilities/ast/DeferredLibraryReferenceDetector.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2014, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.dart.engine.utilities.ast;
+
+import com.google.dart.engine.ast.Expression;
+import com.google.dart.engine.ast.PrefixedIdentifier;
+import com.google.dart.engine.ast.visitor.RecursiveAstVisitor;
+
+/**
+ * This recursive Ast visitor is used to run over {@link Expression}s to determine if the expression
+ * is composed by at least one deferred {@link PrefixedIdentifier}.
+ * 
+ * @see PrefixedIdentifier#isDeferred()
+ */
+public class DeferredLibraryReferenceDetector extends RecursiveAstVisitor<Void> {
+  private boolean result = false;
+
+  /**
+   * Return the result, {@code true} if the visitor found a {@link PrefixedIdentifier} that returned
+   * {@code true} to the {@link PrefixedIdentifier#isDeferred()} query.
+   * 
+   * @return {@code true} if the visitor found a {@link PrefixedIdentifier} that returned
+   *         {@code true} to the {@link PrefixedIdentifier#isDeferred()} query
+   */
+  public boolean getResult() {
+    return result;
+  }
+
+  @Override
+  public Void visitPrefixedIdentifier(PrefixedIdentifier node) {
+    // If result is already true, skip.
+    if (!result) {
+      // Set result to true if isDeferred() is true
+      if (node.isDeferred()) {
+        result = true;
+      }
+    }
+    return null;
+  }
+}