Move the Widget hierarchy to the Oilpan heap.

Source/platform/scroll/ScrollView.cpp

Index: Source/platform/scroll/ScrollView.cpp
diff --git a/Source/platform/scroll/ScrollView.cpp b/Source/platform/scroll/ScrollView.cpp
index e362c659d1378b7ed09bcdb9103402f5a08ef821..3b38d02c2e631f920462244530870f184fabb521 100644
--- a/Source/platform/scroll/ScrollView.cpp
+++ b/Source/platform/scroll/ScrollView.cpp
@@ -51,7 +51,17 @@ 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());
@@ -94,7 +104,7 @@ void ScrollView::setHasVerticalScrollbar(bool hasBar)
     }
 }
 
-PassRefPtr<Scrollbar> ScrollView::createScrollbar(ScrollbarOrientation orientation)
+PassRefPtrWillBeRawPtr<Scrollbar> ScrollView::createScrollbar(ScrollbarOrientation orientation)
 {
     return Scrollbar::create(this, orientation, RegularScrollbar);
 }
@@ -737,8 +747,8 @@ void ScrollView::setFrameRect(const IntRect& newRect)
 
 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();
 }
 
@@ -1075,8 +1085,8 @@ void ScrollView::setParentVisible(bool 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);
 }
 
@@ -1085,8 +1095,8 @@ 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);
         }
     }
@@ -1098,8 +1108,8 @@ 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);