Oilpan: move editing objects to the heap.

Source/core/editing/EditCommand.cpp

Index: Source/core/editing/EditCommand.cpp
diff --git a/Source/core/editing/EditCommand.cpp b/Source/core/editing/EditCommand.cpp
index d8c240c729f67336052b0e39d40567744c9ae488..9f4e60b06c063990f82c7ad3aaf655fb0e47125c 100644
--- a/Source/core/editing/EditCommand.cpp
+++ b/Source/core/editing/EditCommand.cpp
@@ -36,7 +36,7 @@ namespace WebCore {
 
 EditCommand::EditCommand(Document& document)
     : m_document(&document)
-    , m_parent(0)
+    , m_parent(nullptr)
 {
     ASSERT(m_document);
     ASSERT(m_document->frame());
@@ -46,7 +46,7 @@ EditCommand::EditCommand(Document& document)
 
 EditCommand::EditCommand(Document* document, const VisibleSelection& startingSelection, const VisibleSelection& endingSelection)
     : m_document(document)
-    , m_parent(0)
+    , m_parent(nullptr)
 {
     ASSERT(m_document);
     ASSERT(m_document->frame());
@@ -120,4 +120,12 @@ void SimpleEditCommand::doReapply()
     doApply();
 }
 
+void EditCommand::trace(Visitor* visitor)
+{
+    visitor->trace(m_document);
+    visitor->trace(m_startingSelection);
+    visitor->trace(m_endingSelection);
+    visitor->trace(m_parent);
+}
+
 } // namespace WebCore