Use the screen info's scale factor to scale the drag image

third_party/WebKit/public/web/WebView.h

 /*
  * Copyright (C) 2009, 2010, 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 268 matching lines @@
     virtual void setIgnoreViewportTagScaleLimits(bool) = 0;
 
     // Returns the "preferred" contents size, defined as the preferred minimum width of the main document's contents
     // and the minimum height required to display the main document without scrollbars.
     // The returned size has the page zoom factor applied.
     virtual WebSize contentsPreferredMinimumSize() = 0;
 
     // Sets the display mode of the web app.
     virtual void setDisplayMode(WebDisplayMode) = 0;
 
-    // The ratio of the current device's screen DPI to the target device's screen DPI.
-    virtual float deviceScaleFactor() const = 0;
-
     // Sets the ratio as computed by computePageScaleConstraints.
     // TODO(oshima): Remove this once the device scale factor implementation is fully
     // migrated to use zooming mechanism.
     virtual void setDeviceScaleFactor(float) = 0;
 
     // Sets the additional zoom factor used for device scale factor. This is used
     // to scale the content by the device scale factor, without affecting zoom level.
     virtual void setZoomFactorForDeviceScaleFactor(float) = 0;
 
     // Set and reset the device color profile.
@@ skipping 188 matching lines @@
     // context's ability to deal with that failure gracefully can be tested.
     virtual void forceNextDrawingBufferCreationToFail() = 0;
 
 protected:
     ~WebView() {}
 };
 
 } // namespace blink
 
 #endif