Oilpan: Mark TrackDisplayUpdateScope STACK_ALLOCATED

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 28f0ad2d547ce1bf96e7bd594cf91a3a6a0c77c1..d9b5700ca7fd18ed33c33652f5a97190cd6348da 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -151,6 +151,7 @@ static void removeElementFromDocumentMap(HTMLMediaElement* element, Document* do
 }
 
 class TrackDisplayUpdateScope {
+    STACK_ALLOCATED();
 public:
     TrackDisplayUpdateScope(HTMLMediaElement* mediaElement)
     {
@@ -164,7 +165,7 @@ public:
     }
 
 private:
-    HTMLMediaElement* m_mediaElement;
+    RawPtrWillBeMember<HTMLMediaElement> m_mediaElement;
 };
 
 static const AtomicString& AudioKindToString(WebMediaPlayerClient::AudioTrackKind kind)