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

ppapi/c/ppb_message_loop.h

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* From ppb_message_loop.idl modified Thu May  9 14:59:57 2013. */
 
 #ifndef PPAPI_C_PPB_MESSAGE_LOOP_H_
 #define PPAPI_C_PPB_MESSAGE_LOOP_H_
 
@@ skipping 178 matching lines @@
    *     special threads, which include realtime audio threads.
    */
   int32_t (*AttachToCurrentThread)(PP_Resource message_loop);
   /**
    * Runs the thread message loop. Running the message loop is required for you
    * to get issued completion callbacks on the thread.
    *
    * The message loop identified by the argument must have been previously
    * successfully attached to the current thread.
    *
-   * You may not run nested message loops. Since the main thread has an
+   * You may not run nested run loops. Since the main thread has an
    * implicit message loop that the system runs, you may not call Run on the
    * main thread.
    *
    * @return
    *   - PP_OK: The message loop was successfully run. Note that on
    *     success, the message loop will only exit when you call PostQuit().
    *   - PP_ERROR_BADRESOURCE: The given message loop resource is invalid.
    *   - PP_ERROR_WRONG_THREAD: You are attempting to run a message loop that
    *     has not been successfully attached to the current thread. Call
    *     AttachToCurrentThread().
@@ skipping 72 matching lines @@
   int32_t (*PostQuit)(PP_Resource message_loop, PP_Bool should_destroy);
 };
 
 typedef struct PPB_MessageLoop_1_0 PPB_MessageLoop;
 /**
  * @}
  */
 
 #endif  /* PPAPI_C_PPB_MESSAGE_LOOP_H_ */