Fix the comment of PPB_MessageLoop.PostWork()

ppapi/api/ppb_message_loop.idl

Index: ppapi/api/ppb_message_loop.idl
diff --git a/ppapi/api/ppb_message_loop.idl b/ppapi/api/ppb_message_loop.idl
index 10d6d34e68dee80256e5d53de8efd85e9fb74103..5ae00b128a15e6f02a52af95604980b43061cffb 100644
--- a/ppapi/api/ppb_message_loop.idl
+++ b/ppapi/api/ppb_message_loop.idl
@@ -117,7 +117,7 @@ label Chrome {
  *
  *   pp::CompletionCallback callback = factory_.NewOptionalCallback(...);
  *   int32_t result = message_loop.PostWork(callback);
- *   if (result != PP_OK_COMPLETIONPENDING)
+ *   if (result != PP_OK)
  *     callback.Run(result);
  *
  * This will run the callback with an error value, and assumes that the
@@ -231,9 +231,9 @@ interface PPB_MessageLoop {
    * PP_FALSE. It will be queued until the next invocation of Run().
    *
    * @return
-   *   - PP_OK_COMPLETIONPENDING: The work was posted to the message loop's
-   *     queue. As described above, this does not mean that the work has been
-   *     or will be executed (if you never run the message loop after posting).
+   *   - PP_OK: The work was posted to the message loop's queue. As described
+   *     above, this does not mean that the work has been or will be executed
+   *     (if you never run the message loop after posting).
    *   - PP_ERROR_BADRESOURCE: The given message loop resource is invalid.
    *   - PP_ERROR_BADARGUMENT: The function pointer for the completion callback
    *     is null (this will be the case if you pass PP_BlockUntilComplete()).