Drag image should always use the real device scale factor

third_party/WebKit/Source/core/loader/EmptyClients.h

 /*
  * Copyright (C) 2006 Eric Seidel (eric@webkit.org)
  * Copyright (C) 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 120 matching lines @@
     bool tabsToLinks() override { return false; }
 
     IntRect windowResizerRect() const override { return IntRect(); }
 
     void invalidateRect(const IntRect&) override {}
     void scheduleAnimation(Widget*) override {}
 
     IntRect viewportToScreen(const IntRect& r, const Widget*) const override { return r; }
     float windowToViewportScalar(const float s) const override { return s; }
     WebScreenInfo screenInfo() const override { return WebScreenInfo(); }
+    float nonEmulatedDeviceScaleFactor() const { return 1.0f; }
+
     void contentsSizeChanged(LocalFrame*, const IntSize&) const override {}
 
     void showMouseOverURL(const HitTestResult&) override {}
 
     void setToolTip(const String&, TextDirection) override {}
 
     void printDelegate(LocalFrame*) override {}
 
     void enumerateChosenDirectory(FileChooser*) override {}
 
@@ skipping 175 matching lines @@
     ~EmptyContextMenuClient() override {}
     void showContextMenu(const ContextMenu*) override {}
     void clearContextMenu() override {}
 };
 
 CORE_EXPORT void fillWithEmptyClients(Page::PageClients&);
 
 } // namespace blink
 
 #endif // EmptyClients_h