[Oilpan] Fix wrong usage of HashSet<WebGLSharedObject*>

third_party/WebKit/Source/modules/webgl/WebGLContextGroup.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGLContextGroup.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLContextGroup.cpp b/third_party/WebKit/Source/modules/webgl/WebGLContextGroup.cpp
index b11b5f387a096a7e4301a86da93e8619953586dd..8e7a914c140f6e5d478a81c1fd8870412ac66de0 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLContextGroup.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLContextGroup.cpp
@@ -80,7 +80,7 @@ void WebGLContextGroup::addObject(WebGLSharedObject* object)
 void WebGLContextGroup::detachAndRemoveAllObjects()
 {
     while (!m_groupObjects.isEmpty()) {
-        HashSet<WebGLSharedObject*>::iterator it = m_groupObjects.begin();
+        WillBeHeapHashSet<RawPtrWillBeUntracedMember<WebGLSharedObject>>::iterator it = m_groupObjects.begin();
         (*it)->detachContextGroup();
     }
 }