Deprecate PerfCounter and PerfLogger

Author: niloc132

dev/core/src/com/google/gwt/dev/util/PerfCounter.java

@@ -27,7 +27,10 @@
  * A counter which records bunch of statistics for frequently occuring
  * operations. Calculates: count, total time, average time, maximum time
  * & slow operations.
+ *
+ * @deprecated Will be removed in a future release.
  */
+@Deprecated(forRemoval = true, since = "2.13.0")
 public class PerfCounter {
   private static class OperationStats {
     private long count = 0;
@@ -131,6 +134,7 @@ public static void print() {
       return;
     }
     System.out.println("------------- Perf Counters -------------");
+    System.out.println(" DEPRECATED in 2.13, and will be removed in a future release");
     synchronized (operationStats) {
       List<String> keys = new ArrayList<String>(operationStats.keySet());
       Collections.sort(keys);

dev/core/src/com/google/gwt/dev/util/PerfLogger.java

@@ -32,7 +32,9 @@
  * {@code gwt.perflog=true}.
  * </p>
  *
+ * @deprecated Will be removed in a future release.
  */
+@Deprecated(forRemoval = true, since = "2.13.0")
 public class PerfLogger {
 
   private static class Timing {