Replace "nested message loop" with "nested run loop" in comments.

ppapi/api/private/ppb_testing_private.idl

Index: ppapi/api/private/ppb_testing_private.idl
diff --git a/ppapi/api/private/ppb_testing_private.idl b/ppapi/api/private/ppb_testing_private.idl
index c2aed41761501d404e9e23129555eef18d37fdad..d592c19d78924ff28fcc264b583ec388b73b427f 100644
--- a/ppapi/api/private/ppb_testing_private.idl
+++ b/ppapi/api/private/ppb_testing_private.idl
@@ -48,7 +48,7 @@ interface PPB_Testing_Private {
                         [in] PP_Point top_left);
 
   /**
-   * Runs a nested message loop. The plugin will be reentered from this call.
+   * Runs a nested run loop. The plugin will be reentered from this call.
    * This function is used for unit testing the API. The normal pattern is to
    * issue some asynchronous call that has a callback. Then you call
    * RunMessageLoop which will suspend the plugin and go back to processing
@@ -60,7 +60,7 @@ interface PPB_Testing_Private {
   void RunMessageLoop([in] PP_Instance instance);
 
   /**
-   * Posts a quit message for the outermost nested message loop. Use this to
+   * Posts a quit message for the outermost nested run loop. Use this to
    * exit and return back to the caller after you call RunMessageLoop.
    */
   void QuitMessageLoop([in] PP_Instance instance);