WTF::notFound looks too much like a local variable.

Source/core/html/track/TextTrackList.cpp

Index: Source/core/html/track/TextTrackList.cpp
diff --git a/Source/core/html/track/TextTrackList.cpp b/Source/core/html/track/TextTrackList.cpp
index 719f96e35670983cec6df31a55fffb32bfefaefa..763707c7744ac027c5a5d466a6974cb6b2b7e8c0 100644
--- a/Source/core/html/track/TextTrackList.cpp
+++ b/Source/core/html/track/TextTrackList.cpp
@@ -151,7 +151,7 @@ void TextTrackList::invalidateTrackIndexesAfterTrack(TextTrack* track)
         ASSERT_NOT_REACHED();
 
     size_t index = tracks->find(track);
-    if (index == notFound)
+    if (index == kNotFound)
         return;
 
     for (size_t i = index; i < tracks->size(); ++i)
@@ -200,7 +200,7 @@ void TextTrackList::remove(TextTrack* track)
     }
 
     size_t index = tracks->find(track);
-    if (index == notFound)
+    if (index == kNotFound)
         return;
 
     invalidateTrackIndexesAfterTrack(track);
@@ -227,7 +227,7 @@ bool TextTrackList::contains(TextTrack* track) const
     else
         ASSERT_NOT_REACHED();
 
-    return tracks->find(track) != notFound;
+    return tracks->find(track) != kNotFound;
 }
 
 const AtomicString& TextTrackList::interfaceName() const