[oilpan] The Node hierarchy should have correct accept method chains

Source/core/html/HTMLMediaElement.cpp

Index: Source/core/html/HTMLMediaElement.cpp
diff --git a/Source/core/html/HTMLMediaElement.cpp b/Source/core/html/HTMLMediaElement.cpp
index 42cc83a9bf4b607fcb738555d6388a217896763d..4a606d44d8eb1a050e84d780006e2daf24bb9592 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -3068,6 +3068,7 @@ KURL HTMLMediaElement::selectNextSourceChild(ContentType* contentType, String* k
     getChildNodes(this, potentialSourceNodes);
 
     for (unsigned i = 0; !canUseSourceElement && i < potentialSourceNodes.size(); ++i) {
+        HandleScope scope;
         node = potentialSourceNodes[i].get();
         if (lookingForStartNode && m_nextChildNodeToConsider != node)
             continue;
@@ -4458,4 +4459,9 @@ void HTMLMediaElement::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) con
 
 }
 
+void HTMLMediaElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLElement::acceptHeapVisitor(visitor);
+}
+
 }