Move the Widget hierarchy to the Oilpan heap.

Source/platform/scroll/ScrollView.cpp

 /*
  * Copyright (C) 2006, 2007, 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 33 matching lines @@
     , m_inUpdateScrollbars(false)
     , m_drawPanScrollIcon(false)
     , m_clipsRepaints(true)
 {
 }
 
 ScrollView::~ScrollView()
 {
 }
 
-void ScrollView::addChild(PassRefPtr<Widget> prpChild)
+void ScrollView::trace(Visitor* visitor)
+{
+#if ENABLE(OILPAN)
+    visitor->trace(m_horizontalScrollbar);
+    visitor->trace(m_verticalScrollbar);
+    visitor->trace(m_children);
+#endif
+    Widget::trace(visitor);
+}
+
+void ScrollView::addChild(PassRefPtrWillBeRawPtr<Widget> prpChild)
 {
     Widget* child = prpChild.get();
     ASSERT(child != this && !child->parent());
     child->setParent(this);
     m_children.add(prpChild);
 }
 
 void ScrollView::removeChild(Widget* child)
 {
     ASSERT(child->parent() == this);
@@ skipping 30 matching lines @@
         willRemoveScrollbar(m_verticalScrollbar.get(), VerticalScrollbar);
         // If the scrollbar has been marked as overlapping the window resizer,
         // then its removal should reduce the count.
         if (m_verticalScrollbar->overlapsResizer())
             adjustScrollbarsAvoidingResizerCount(-1);
         removeChild(m_verticalScrollbar.get());
         m_verticalScrollbar = nullptr;
     }
 }
 
-PassRefPtr<Scrollbar> ScrollView::createScrollbar(ScrollbarOrientation orientation)
+PassRefPtrWillBeRawPtr<Scrollbar> ScrollView::createScrollbar(ScrollbarOrientation orientation)
 {
     return Scrollbar::create(this, orientation, RegularScrollbar);
 }
 
 void ScrollView::setScrollbarModes(ScrollbarMode horizontalMode, ScrollbarMode verticalMode,
                                    bool horizontalLock, bool verticalLock)
 {
     bool needsUpdate = false;
 
     if (horizontalMode != horizontalScrollbarMode() && !m_horizontalScrollbarLock) {
@@ skipping 653 matching lines @@
 
     Widget::setFrameRect(newRect);
 
     updateScrollbars(scrollOffset());
 
     frameRectsChanged();
 }
 
 void ScrollView::frameRectsChanged()
 {
-    HashSet<RefPtr<Widget> >::const_iterator end = m_children.end();
-    for (HashSet<RefPtr<Widget> >::const_iterator current = m_children.begin(); current != end; ++current)
+    ChildrenWidgetSet::const_iterator end = m_children.end();
+    for (ChildrenWidgetSet::const_iterator current = m_children.begin(); current != end; ++current)
         (*current)->frameRectsChanged();
 }
 
 static void positionScrollbarLayer(GraphicsLayer* graphicsLayer, Scrollbar* scrollbar)
 {
     if (!graphicsLayer || !scrollbar)
         return;
 
     IntRect scrollbarRect = scrollbar->frameRect();
     graphicsLayer->setPosition(scrollbarRect.location());
@@ skipping 316 matching lines @@
 void ScrollView::setParentVisible(bool visible)
 {
     if (isParentVisible() == visible)
         return;
 
     Widget::setParentVisible(visible);
 
     if (!isSelfVisible())
         return;
 
-    HashSet<RefPtr<Widget> >::iterator end = m_children.end();
-    for (HashSet<RefPtr<Widget> >::iterator it = m_children.begin(); it != end; ++it)
+    ChildrenWidgetSet::const_iterator end = m_children.end();
+    for (ChildrenWidgetSet::const_iterator it = m_children.begin(); it != end; ++it)
         (*it)->setParentVisible(visible);
 }
 
 void ScrollView::show()
 {
     if (!isSelfVisible()) {
         setSelfVisible(true);
         if (isParentVisible()) {
-            HashSet<RefPtr<Widget> >::iterator end = m_children.end();
-            for (HashSet<RefPtr<Widget> >::iterator it = m_children.begin(); it != end; ++it)
+            ChildrenWidgetSet::const_iterator end = m_children.end();
+            for (ChildrenWidgetSet::const_iterator it = m_children.begin(); it != end; ++it)
                 (*it)->setParentVisible(true);
         }
     }
 
     Widget::show();
 }
 
 void ScrollView::hide()
 {
     if (isSelfVisible()) {
         if (isParentVisible()) {
-            HashSet<RefPtr<Widget> >::iterator end = m_children.end();
-            for (HashSet<RefPtr<Widget> >::iterator it = m_children.begin(); it != end; ++it)
+            ChildrenWidgetSet::const_iterator end = m_children.end();
+            for (ChildrenWidgetSet::const_iterator it = m_children.begin(); it != end; ++it)
                 (*it)->setParentVisible(false);
         }
         setSelfVisible(false);
     }
 
     Widget::hide();
 }
 
 void ScrollView::addPanScrollIcon(const IntPoint& iconPosition)
 {
@@ skipping 20 matching lines @@
         return;
 
     ScrollableArea::setScrollOrigin(origin);
 
     // Update if the scroll origin changes, since our position will be different if the content size did not change.
     if (updatePositionAtAll && updatePositionSynchronously)
         updateScrollbars(scrollOffset());
 }
 
 } // namespace blink