Move the Widget hierarchy to the Oilpan heap.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 56daf3fa7c175de830ec03d437b239fb96797b3a..7f0742cfad04c231aae71f08de7aa1f489d07dcc 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -1914,7 +1914,7 @@ void Document::updateLayout()
 
     ScriptForbiddenScope forbidScript;
 
-    RefPtr<FrameView> frameView = view();
+    RefPtrWillBeRawPtr<FrameView> frameView = view();
     if (frameView && frameView->isInPerformLayout()) {
         // View layout should not be re-entrant.
         ASSERT_NOT_REACHED();