Don't call into ScrollView from Scrollbar.

Source/platform/scroll/Scrollbar.cpp

 /*
  * Copyright (C) 2004, 2006, 2008 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 13 matching lines @@
  */
 
 #include "config.h"
 #include "platform/scroll/Scrollbar.h"
 
 #include <algorithm>
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/PlatformGestureEvent.h"
 #include "platform/PlatformMouseEvent.h"
 #include "platform/scroll/ScrollAnimator.h"
-#include "platform/scroll/ScrollView.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "platform/scroll/ScrollbarTheme.h"
 
 #if ((OS(POSIX) && !OS(MACOSX)) || OS(WIN))
 // The position of the scrollbar thumb affects the appearance of the steppers, so
 // when the thumb moves, we have to invalidate them for painting.
 #define THUMB_POSITION_AFFECTS_BUTTONS
 #endif
 
 namespace blink {
@@ skipping 38 matching lines @@
     m_currentPos = scrollableAreaCurrentPos();
 }
 
 Scrollbar::~Scrollbar()
 {
     stopTimerIfNeeded();
 
     m_theme->unregisterScrollbar(this);
 }
 
-void Scrollbar::removeFromParent()
-{
-    if (parent())
-        toScrollView(parent())->removeChild(this);
-}
-
-ScrollView* Scrollbar::parentScrollView() const
-{
-    return parent() && parent()->isScrollView() ? toScrollView(parent()) : 0;
-}
-
 ScrollbarOverlayStyle Scrollbar::scrollbarOverlayStyle() const
 {
     return m_scrollableArea ? m_scrollableArea->scrollbarOverlayStyle() : ScrollbarOverlayStyleDefault;
 }
 
 void Scrollbar::getTickmarks(Vector<IntRect>& tickmarks) const
 {
     if (m_scrollableArea)
         m_scrollableArea->getTickmarks(tickmarks);
 }
 
 bool Scrollbar::isScrollableAreaActive() const
 {
     return m_scrollableArea && m_scrollableArea->isActive();
 }
 
 bool Scrollbar::isScrollViewScrollbar() const
 {
-    return parent() && parent()->isFrameView() && toScrollView(parent())->isScrollViewScrollbar(this);

[Ian Vollick, 2014/10/04 01:25:45]

Wouldn't this have previously returned true for RenderLayerScrollableArea's
scrollbars, but will now return false
m_scrollableArea->isScrollViewScrollbar(this) will hit
ScrollableArea::isScrollViewScrollbar(...) which you've made to return false?

[skobes, 2014/10/06 18:18:53]

No, ScrollView::isScrollViewScrollbar returns false if you pass it a scrollbar
that belongs to a RenderLayerScrollableArea.

+    return m_scrollableArea && m_scrollableArea->isScrollViewScrollbar(this);
 }
 
 bool Scrollbar::isLeftSideVerticalScrollbar() const
 {
     if (m_orientation == VerticalScrollbar && m_scrollableArea)
         return m_scrollableArea->shouldPlaceVerticalScrollbarOnLeft();
     return false;
 }
 
 void Scrollbar::offsetDidChange()
@@ skipping 331 matching lines @@
         moveThumb(desiredPos);
         return;
     } else if (m_pressedPart == ThumbPart)
         m_dragOrigin = m_currentPos;
 
     m_pressedPos = pressedPos;
 
     autoscrollPressedPart(theme()->initialAutoscrollTimerDelay());
 }
 
-void Scrollbar::setFrameRect(const IntRect& rect)
-{
-    // Get our window resizer rect and see if we overlap. Adjust to avoid the overlap
-    // if necessary.
-    IntRect adjustedRect(rect);
-    bool overlapsResizer = false;
-    ScrollView* view = parentScrollView();
-    if (view && !rect.isEmpty() && !view->windowResizerRect().isEmpty()) {
-        IntRect resizerRect = view->convertFromContainingWindow(view->windowResizerRect());
-        if (rect.intersects(resizerRect)) {
-            if (orientation() == HorizontalScrollbar) {
-                int overlap = rect.maxX() - resizerRect.x();
-                if (overlap > 0 && resizerRect.maxX() >= rect.maxX()) {
-                    adjustedRect.setWidth(rect.width() - overlap);
-                    overlapsResizer = true;
-                }
-            } else {
-                int overlap = rect.maxY() - resizerRect.y();
-                if (overlap > 0 && resizerRect.maxY() >= rect.maxY()) {
-                    adjustedRect.setHeight(rect.height() - overlap);
-                    overlapsResizer = true;
-                }
-            }
-        }
-    }
-    if (overlapsResizer != m_overlapsResizer) {
-        m_overlapsResizer = overlapsResizer;
-        if (view)
-            view->adjustScrollbarsAvoidingResizerCount(m_overlapsResizer ? 1 : -1);
-    }
-
-    Widget::setFrameRect(adjustedRect);
-}
-
-void Scrollbar::setParent(Widget* parentView)
-{
-    if (!parentView && m_overlapsResizer && parentScrollView())
-        parentScrollView()->adjustScrollbarsAvoidingResizerCount(-1);
-    Widget::setParent(parentView);
-}
-
 void Scrollbar::setEnabled(bool e)
 {
     if (m_enabled == e)
         return;
     m_enabled = e;
     theme()->updateEnabledState(this);
     invalidate();
 }
 
 bool Scrollbar::isOverlayScrollbar() const
@@ skipping 60 matching lines @@
     if (!m_scrollableArea)
         return 0;
 
     if (m_orientation == HorizontalScrollbar)
         return m_scrollableArea->scrollPosition().x() - m_scrollableArea->minimumScrollPosition().x();
 
     return m_scrollableArea->scrollPosition().y() - m_scrollableArea->minimumScrollPosition().y();
 }
 
 } // namespace blink