Determine the layoutobject of middleClickAutoscroll by the scroll direction.

third_party/WebKit/Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1025 matching lines @@
         layoutObject->document().localOwner())
       layoutObject = layoutObject->document().localOwner()->layoutObject();
     else
       layoutObject = layoutObject->parent();
   }
 
   return layoutObject && layoutObject->isBox() ? toLayoutBox(layoutObject)
                                                : nullptr;
 }
 
-static inline int adjustedScrollDelta(int beginningDelta) {
-  // This implemention matches Firefox's.
-  // http://mxr.mozilla.org/firefox/source/toolkit/content/widgets/browser.xml#856.
-  const int speedReducer = 12;
-
-  int adjustedDelta = beginningDelta / speedReducer;
-  if (adjustedDelta > 1)
-    adjustedDelta = static_cast<int>(adjustedDelta *
-                                     sqrt(static_cast<double>(adjustedDelta))) -
-                    1;
-  else if (adjustedDelta < -1)
-    adjustedDelta =
-        static_cast<int>(adjustedDelta *
-                         sqrt(static_cast<double>(-adjustedDelta))) +
-        1;
-
-  return adjustedDelta;
-}
-
-static inline IntSize adjustedScrollDelta(const IntSize& delta) {
-  return IntSize(adjustedScrollDelta(delta.width()),
-                 adjustedScrollDelta(delta.height()));
-}
-
-void LayoutBox::middleClickAutoscroll(const IntPoint& sourcePoint) {
-  LocalFrame* frame = this->frame();
-  if (!frame)
-    return;
-
-  IntPoint lastKnownMousePosition =
-      frame->eventHandler().lastKnownMousePosition();
-
-  // We need to check if the last known mouse position is out of the window.
-  // When the mouse is out of the window, the position is incoherent
-  static IntPoint previousMousePosition;
-  if (lastKnownMousePosition.x() < 0 || lastKnownMousePosition.y() < 0)
-    lastKnownMousePosition = previousMousePosition;
-  else
-    previousMousePosition = lastKnownMousePosition;
-
-  IntSize delta = lastKnownMousePosition - sourcePoint;
-
-  // at the center we let the space for the icon.
-  if (abs(delta.width()) <= AutoscrollController::noMiddleClickAutoscrollRadius)
-    delta.setWidth(0);
-  if (abs(delta.height()) <=
-      AutoscrollController::noMiddleClickAutoscrollRadius)
-    delta.setHeight(0);
-  scroll(ScrollByPixel, FloatSize(adjustedScrollDelta(delta)));
-}
-
 void LayoutBox::scrollByRecursively(const ScrollOffset& delta) {
   if (delta.isZero())
     return;
 
   bool restrictedByLineClamp = false;
   if (parent())
     restrictedByLineClamp = !parent()->style()->lineClamp().isNone();
 
   if (hasOverflowClip() && !restrictedByLineClamp) {
     PaintLayerScrollableArea* scrollableArea = this->getScrollableArea();
@@ skipping 4537 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink