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

ash/drag_drop/drag_drop_controller.cc

 // 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.
 
 #include "ash/drag_drop/drag_drop_controller.h"
 
 #include <utility>
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
@@ skipping 484 matching lines @@
 // DragDropController, private:
 
 void DragDropController::AnimationEnded(const gfx::Animation* animation) {
   cancel_animation_.reset();
 
   // By the time we finish animation, another drag/drop session may have
   // started. We do not want to destroy the drag image in that case.
   if (!IsDragDropInProgress())
     drag_image_.reset();
   if (pending_long_tap_) {
-    // If not in a nested message loop, we can forward the long tap right now.
+    // If not in a nested run loop, we can forward the long tap right now.
     if (!should_block_during_drag_drop_) {
       ForwardPendingLongTap();
     } else {
       // See comment about this in OnGestureEvent().
       base::ThreadTaskRunnerHandle::Get()->PostTask(
           FROM_HERE, base::Bind(&DragDropController::ForwardPendingLongTap,
                                 weak_factory_.GetWeakPtr()));
     }
   }
 }
@@ skipping 59 matching lines @@
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   // Cleanup can be called again while deleting DragDropTracker, so delete
   // the pointer with a local variable to avoid double free.
   std::unique_ptr<ash::DragDropTracker> holder = std::move(drag_drop_tracker_);
 }
 
 }  // namespace ash