Change Timer.java to allow 0ms delay for single shot timers.

Review at http://gwt-code-reviews.appspot.com/1506802


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10780 8db76d5a-ed1c-0410-87a9-c151d255dfc7

user/src/com/google/gwt/user/client/Timer.java

diff --git a/user/src/com/google/gwt/user/client/Timer.java b/user/src/com/google/gwt/user/client/Timer.java
index 13333b1..fc6e375 100644
--- a/user/src/com/google/gwt/user/client/Timer.java
+++ b/user/src/com/google/gwt/user/client/Timer.java
@@ -110,8 +110,8 @@
    *          milliseconds
    */
   public void schedule(int delayMillis) {
-    if (delayMillis <= 0) {
-      throw new IllegalArgumentException("must be positive");
+    if (delayMillis < 0) {
+      throw new IllegalArgumentException("must be non-negative");
     }
     cancel();
     isRepeating = false;