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

ppapi/cpp/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.
 
 #ifndef PPAPI_CPP_MESSAGE_LOOP_H_
 #define PPAPI_CPP_MESSAGE_LOOP_H_
 
 #include <stdint.h>
 
 #include "ppapi/cpp/resource.h"
@@ skipping 166 matching lines @@
   ///     loop attached to it. See the interface level discussion about these
   ///     special threads, which include realtime audio threads.
   int32_t AttachToCurrentThread();
 
   /// 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 63 matching lines @@
   ///   - PP_ERROR_BADRESOURCE: The message loop was invalid.
   ///   - PP_ERROR_WRONG_THREAD: You are attempting to quit the main thread.
   ///     The main thread's message loop is managed by the system and can't be
   ///     quit.
   int32_t PostQuit(bool should_destroy);
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_MESSAGE_LOOP_H_