[MD] fix bookmark bar/URL bar drag image color for OTR mode.

ui/views/drag_utils.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 "ui/views/drag_utils.h"
 
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
 
 float GetDeviceScaleForNativeView(views::Widget* widget) {
   float device_scale = 1.0f;
-  // The following code should work on other platforms as well. But we do not
-  // yet care about device scale factor on other platforms. So to keep drag and
-  // drop behavior on other platforms un-touched, we wrap this in the #if guard.
   if (widget && widget->GetNativeView()) {
     gfx::NativeView view = widget->GetNativeView();
     gfx::Display display = gfx::Screen::GetScreenFor(view)->
         GetDisplayNearestWindow(view);
     device_scale = display.device_scale_factor();
   }
   return device_scale;
 }
 
 }  // namespace
 
 namespace views {
 
 gfx::Canvas* GetCanvasForDragImage(views::Widget* widget,
                                    const gfx::Size& canvas_size) {
   float device_scale = GetDeviceScaleForNativeView(widget);
   return new gfx::Canvas(canvas_size, device_scale, false);
 }
 
 }  // namespace views