Adds deprecation to @GwtScriptOnly

Change-Id: I6e243604c72dd2d8377146a384e9921e586a08a6
diff --git a/dev/core/super/com/google/gwt/core/client/GwtScriptOnly.java b/dev/core/super/com/google/gwt/core/client/GwtScriptOnly.java
index 9d8406b..d1e7127 100644
--- a/dev/core/super/com/google/gwt/core/client/GwtScriptOnly.java
+++ b/dev/core/super/com/google/gwt/core/client/GwtScriptOnly.java
@@ -34,8 +34,11 @@
  * being parsed and loaded for Development Mode. This is done under certain
  * circumstances as an optimization to avoid loading very large jsni methods
  * which are only executed in Production Mode.
+ *
+ * @deprecated since hosted/dev mode is deprecated and has no other uses.
  */
 @Documented
 @Target({ElementType.TYPE, ElementType.METHOD})
+@Deprecated
 public @interface GwtScriptOnly {
 }