Oilpan: improve ScrollableArea handling.

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 62 matching lines @@
 
     m_theme->registerScrollbar(this);
 
     // FIXME: This is ugly and would not be necessary if we fix cross-platform code to actually query for
     // scrollbar thickness and use it when sizing scrollbars (rather than leaving one dimension of the scrollbar
     // alone when sizing).
     int thickness = m_theme->scrollbarThickness(controlSize);
     Widget::setFrameRect(IntRect(0, 0, thickness, thickness));
 
     m_currentPos = scrollableAreaCurrentPos();
-
-#if ENABLE(OILPAN)
-    if (m_scrollableArea)
-        m_animator = m_scrollableArea->scrollAnimator();
-#endif
 }
 
 Scrollbar::~Scrollbar()
 {
-    stopTimerIfNeeded();
+    m_theme->unregisterScrollbar(this);
+}
 
-    m_theme->unregisterScrollbar(this);
-
-#if ENABLE(OILPAN)
-    if (!m_animator)
-        return;
-
-    ASSERT(m_scrollableArea);
-    if (m_orientation == VerticalScrollbar)
-        m_animator->willRemoveVerticalScrollbar(this);
-    else
-        m_animator->willRemoveHorizontalScrollbar(this);
-#endif
+DEFINE_TRACE(Scrollbar)
+{
+    visitor->trace(m_scrollableArea);
+    Widget::trace(visitor);
 }
 
 void Scrollbar::setFrameRect(const IntRect& frameRect)
 {
     if (frameRect == this->frameRect())
         return;
 
     invalidate();
     Widget::setFrameRect(frameRect);
     invalidate();
@@ skipping 30 matching lines @@
     if (position == m_currentPos)
         return;
 
     int oldThumbPosition = theme()->thumbPosition(this);
     m_currentPos = position;
     updateThumbPosition();
     if (m_pressedPart == ThumbPart)
         setPressedPos(m_pressedPos + theme()->thumbPosition(this) - oldThumbPosition);
 }
 
 void Scrollbar::disconnectFromScrollableArea()

[haraken, 2015/06/30 10:30:36]

I'd add #if !ENABLE(OILPAN).

 {
     m_scrollableArea = nullptr;
-#if ENABLE(OILPAN)
-    m_animator = nullptr;
-#endif
 }
 
 void Scrollbar::setProportion(int visibleSize, int totalSize)
 {
     if (visibleSize == m_visibleSize && totalSize == m_totalSize)
         return;
 
     m_visibleSize = visibleSize;
     m_totalSize = totalSize;
 
@@ skipping 393 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