Remove --ash-enable-tray-dragging flag

ash/wm/gestures/shelf_gesture_handler.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/wm/gestures/shelf_gesture_handler.h"
 
 #include "ash/root_window_controller.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_types.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/system/status_area_widget.h"
-#include "ash/wm/gestures/tray_gesture_handler.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/window_util.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/transform.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 
@@ skipping 31 matching lines @@
   if (event.type() == ui::ET_GESTURE_SCROLL_BEGIN) {
     drag_in_progress_ = true;
     shelf->StartGestureDrag(event);
     return true;
   }
 
   if (!drag_in_progress_)
     return false;
 
   if (event.type() == ui::ET_GESTURE_SCROLL_UPDATE) {
-    if (tray_handler_) {
-      if (!tray_handler_->UpdateGestureDrag(event))
-        tray_handler_.reset();
-    } else if (shelf->UpdateGestureDrag(event) ==
-        ShelfLayoutManager::DRAG_TRAY) {
-      tray_handler_.reset(new TrayGestureHandler());
-    }
-
+    shelf->UpdateGestureDrag(event);
     return true;
   }
 
   drag_in_progress_ = false;
 
   if (event.type() == ui::ET_GESTURE_SCROLL_END ||
       event.type() == ui::ET_SCROLL_FLING_START) {
-    if (tray_handler_) {
-      tray_handler_->CompleteGestureDrag(event);
-      tray_handler_.reset();
-    }
-
     shelf->CompleteGestureDrag(event);
     return true;
   }
 
   // Unexpected event. Reset the state and let the event fall through.
   shelf->CancelGestureDrag();
   return false;
 }
 
 }  // namespace ash