Adding no-op methods to return synchronized collection in gwt

Change-Id: I6f1dc3b449df2a0430fd71752ed53a91c0491651

user/super/com/google/gwt/emul/java/util/Collections.java

diff --git a/user/super/com/google/gwt/emul/java/util/Collections.java b/user/super/com/google/gwt/emul/java/util/Collections.java
index 8ad6e6b..ec35c32 100644
--- a/user/super/com/google/gwt/emul/java/util/Collections.java
+++ b/user/super/com/google/gwt/emul/java/util/Collections.java
@@ -295,6 +295,62 @@
   }
 
   /*
+   * Returns the input collection as it is.
+   */
+  public static <T> Collection<T> synchronizedCollection(Collection<T> c) {
+    return c;
+  }
+
+  /*
+   * Returns the input list as it is.
+   */
+  public static <T> List<T> synchronizedList(List<T> list) {
+    return list;
+  }
+
+  /*
+   * Returns the input map as it is.
+   */
+  public static <K, V> Map<K, V> synchronizedMap(Map<K, V> m) {
+    return m;
+  }
+
+  /*
+   * Returns the input map as it is.
+   */
+  public static <K, V> NavigableMap<K, V> synchronizedNavigableMap(NavigableMap<K, V> m) {
+    return m;
+  }
+
+  /*
+   * Returns the input set as it is.
+   */
+  public static <T> NavigableSet<T> synchronizedNavigableSet(NavigableSet<T> s) {
+    return s;
+  }
+
+  /*
+   * Returns the input set as it is.
+   */
+  public static <T> Set<T> synchronizedSet(Set<T> s) {
+    return s;
+  }
+
+  /*
+   * Returns the input map as it is.
+   */
+  public static <K, V> SortedMap<K, V> synchronizedSortedMap(SortedMap<K, V> m) {
+    return m;
+  }
+
+  /*
+   * Returns the input set as it is.
+   */
+  public static <T> SortedSet<T> synchronizedSortedSet(SortedSet<T> s) {
+    return s;
+  }
+
+  /*
    * TODO: make the unmodifiable collections serializable.
    */