ash: Do not use MessageLoopForUI when not needed.

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"
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/run_loop.h"
+#include "base/thread_task_runner_handle.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/hit_test.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
@@ skipping 189 matching lines @@
 
   drag_window_ = NULL;
 
   // Ends cancel animation if it's in progress.
   if (cancel_animation_)
     cancel_animation_->End();
 
   if (should_block_during_drag_drop_) {
     base::RunLoop run_loop;
     quit_closure_ = run_loop.QuitClosure();
-    base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
+    base::MessageLoop* loop = base::MessageLoop::current();
     base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
     run_loop.Run();
   }
 
   if (drag_operation_ == 0) {
     UMA_HISTOGRAM_ENUMERATION("Event.DragDrop.Cancel", source,
                               ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
   } else {
     UMA_HISTOGRAM_ENUMERATION("Event.DragDrop.Drop", source,
                               ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
@@ skipping 258 matching lines @@
   // 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 (!should_block_during_drag_drop_) {
       ForwardPendingLongTap();
     } else {
       // See comment about this in OnGestureEvent().
-      base::MessageLoopForUI::current()->PostTask(
-          FROM_HERE,
-          base::Bind(&DragDropController::ForwardPendingLongTap,
-                     weak_factory_.GetWeakPtr()));
+      base::ThreadTaskRunnerHandle::Get()->PostTask(
+          FROM_HERE, base::Bind(&DragDropController::ForwardPendingLongTap,
+                                weak_factory_.GetWeakPtr()));
     }
   }
 }
 
 void DragDropController::DoDragCancel(int drag_cancel_animation_duration_ms) {
   ash::Shell::GetInstance()->cursor_manager()->SetCursor(ui::kCursorPointer);
 
   // |drag_window_| can be NULL if we have just started the drag and have not
   // received any DragUpdates, or, if the |drag_window_| gets destroyed during
   // a drag/drop.
@@ skipping 46 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.
   scoped_ptr<ash::DragDropTracker> holder = std::move(drag_drop_tracker_);
 }
 
 }  // namespace ash