Reverting r7403 because it is causing RpcValueTypesTest to fail.

Patch by: jlabanca



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7406 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/src/com/google/gwt/user/server/rpc/impl/SerializabilityUtil.java b/user/src/com/google/gwt/user/server/rpc/impl/SerializabilityUtil.java
index 067dbaa..c1b298a 100644
--- a/user/src/com/google/gwt/user/server/rpc/impl/SerializabilityUtil.java
+++ b/user/src/com/google/gwt/user/server/rpc/impl/SerializabilityUtil.java
@@ -238,7 +238,7 @@
   private static Class<?> computeHasCustomFieldSerializer(Class<?> instanceType) {
     assert (instanceType != null);
     String qualifiedTypeName = instanceType.getName();
-    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+    ClassLoader classLoader = SerializabilityUtil.class.getClassLoader();
     String simpleSerializerName = qualifiedTypeName + "_CustomFieldSerializer";
     Class<?> customSerializer = getCustomFieldSerializer(classLoader,
         simpleSerializerName);