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

base/message_loop/message_loop.h

 // Copyright 2013 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 BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 
 #include <memory>
 #include <queue>
 #include <string>
@@ skipping 387 matching lines @@
   bool in_high_res_mode_;
 #endif
 
   // Contains delayed tasks, sorted by their 'delayed_run_time' property.
   DelayedTaskQueue delayed_work_queue_;
 
   // A recent snapshot of Time::Now(), used to check delayed_work_queue_.
   TimeTicks recent_time_;
 
   // A queue of non-nestable tasks that we had to defer because when it came
-  // time to execute them we were in a nested message loop.  They will execute
-  // once we're out of nested message loops.
+  // time to execute them we were in a nested run loop.  They will execute
+  // once we're out of nested run loops.
   TaskQueue deferred_non_nestable_work_queue_;
 
   ObserverList<DestructionObserver> destruction_observers_;
 
   // A recursion block that prevents accidentally running additional tasks when
   // insider a (accidentally induced?) nested message pump.
   bool nestable_tasks_allowed_;
 
   // pump_factory_.Run() is called to create a message pump for this loop
   // if type_ is TYPE_CUSTOM and pump_ is null.
@@ skipping 171 matching lines @@
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 static_assert(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
               "MessageLoopForIO should not have extra member variables");
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_