Revert of [Oilpan] Migrate classes under module/webgl onto oilpan heap

Source/modules/webgl/WebGLObject.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 51 matching lines @@
     }
 }
 
 void WebGLObject::detach()
 {
     m_attachmentCount = 0; // Make sure OpenGL resource is deleted.
 }
 
 void WebGLObject::detachAndDeleteObject()
 {
-    // To ensure that all platform objects are deleted after being detached,
-    // this method does them together.
+    // Helper method that pairs detachment with platform object
+    // deletion.
     //
-    // The individual WebGL destructors need to call detachAndDeleteObject()
-    // rather than do it based on Oilpan GC.
+    // With Oilpan enabled, objects may end up being finalized without
+    // having been detached first. Consequently, the objects force
+    // detachment first before deleting the platform object. Without
+    // Oilpan, the objects will have been detached from the 'parent'
+    // objects first and do not separately require it when finalizing.
+    //
+    // However, as detach() is trivial, the individual WebGL
+    // destructors will always call detachAndDeleteObject() rather
+    // than do it based on Oilpan being enabled.
     detach();
     deleteObject(nullptr);
 }
 
 void WebGLObject::onDetached(WebGraphicsContext3D* context3d)
 {
     if (m_attachmentCount)
         --m_attachmentCount;
     if (m_deleted)
         deleteObject(context3d);
 }
 
 } // namespace blink