Remove --ash-enable-tray-dragging flag

ash/wm/gestures/tray_gesture_handler.h

Index: ash/wm/gestures/tray_gesture_handler.h
diff --git a/ash/wm/gestures/tray_gesture_handler.h b/ash/wm/gestures/tray_gesture_handler.h
deleted file mode 100644
index 529349868c81c453cb754b37731bd2071794ef83..0000000000000000000000000000000000000000
--- a/ash/wm/gestures/tray_gesture_handler.h
+++ /dev/null
@@ -1,46 +0,0 @@
-// 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 ASH_WM_GESTURES_TRAY_GESTURE_HANDLER_H_
-#define ASH_WM_GESTURES_TRAY_GESTURE_HANDLER_H_
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "ui/views/widget/widget_observer.h"
-
-namespace ui {
-class GestureEvent;
-}
-
-namespace ash {
-
-// Handles gesture events on the shelf to show the system tray bubble.
-class TrayGestureHandler : public views::WidgetObserver {
- public:
-  TrayGestureHandler();
-  ~TrayGestureHandler() override;
-
-  // Handles a gesture-update event and updates the dragging state of the tray
-  // bubble. Returns true if the handler can continue to process gesture events
-  // for the bubble. Returns false if it should no longer receive gesture
-  // events.
-  bool UpdateGestureDrag(const ui::GestureEvent& event);
-
-  void CompleteGestureDrag(const ui::GestureEvent& event);
-
- private:
-  void OnWidgetDestroying(views::Widget* widget) override;
-
-  // The widget for the tray-bubble.
-  views::Widget* widget_;
-
-  // The amount that has been dragged.
-  float gesture_drag_amount_;
-
-  DISALLOW_COPY_AND_ASSIGN(TrayGestureHandler);
-};
-
-}  // namespace ash
-
-#endif  // ASH_WM_GESTURES_TRAY_GESTURE_HANDLER_H_