Remove unused GCObject class.

third_party/WebKit/Source/platform/heap/PersistentNode.cpp

Index: third_party/WebKit/Source/platform/heap/PersistentNode.cpp
diff --git a/third_party/WebKit/Source/platform/heap/PersistentNode.cpp b/third_party/WebKit/Source/platform/heap/PersistentNode.cpp
index df3cfa7cc5aa87459c4fd3d9410e731d32b2c9ef..f04607740e9eb5bf7774660a44243ba930e47d59 100644
--- a/third_party/WebKit/Source/platform/heap/PersistentNode.cpp
+++ b/third_party/WebKit/Source/platform/heap/PersistentNode.cpp
@@ -119,14 +119,6 @@ void PersistentRegion::tracePersistentNodes(Visitor* visitor)
     ASSERT(persistentCount == m_persistentCount);
 }
 
-
-namespace {
-class GCObject final : public GarbageCollected<GCObject> {
-public:
-    DEFINE_INLINE_TRACE() { }
-};
-}
-
 void CrossThreadPersistentRegion::prepareForThreadStateTermination(ThreadState* threadState)
 {
     // For heaps belonging to a thread that's detaching, any cross-thread persistents