[wrapper-tracing] Fix WebGL extension and attachment handling

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.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 7693 matching lines @@
   visitor->traceWrappers(m_boundVertexArrayObject);
   // Trace wrappers explicitly here since TextureUnitState is not a heap
   // object, i.e., we cannot set its mark bits.
   for (auto& unit : m_textureUnits) {
     visitor->traceWrappers(unit.m_texture2DBinding);
     visitor->traceWrappers(unit.m_textureCubeMapBinding);
     visitor->traceWrappers(unit.m_texture3DBinding);
     visitor->traceWrappers(unit.m_texture2DArrayBinding);
   }
   for (ExtensionTracker* tracker : m_extensions) {
-    WebGLExtension* extension = tracker->getExtensionObjectIfAlreadyEnabled();
-    visitor->traceWrappers(extension);
+    visitor->traceWrappers(tracker);
   }
   CanvasRenderingContext::traceWrappers(visitor);
 }
 
 int WebGLRenderingContextBase::externallyAllocatedBytesPerPixel() {
   if (isContextLost())
     return 0;
 
   int bytesPerPixel = 4;
   int totalBytesPerPixel =
@@ skipping 36 matching lines @@
 
 void WebGLRenderingContextBase::getHTMLOrOffscreenCanvas(
     HTMLCanvasElementOrOffscreenCanvas& result) const {
   if (canvas())
     result.setHTMLCanvasElement(canvas());
   else
     result.setOffscreenCanvas(getOffscreenCanvas());
 }
 
 }  // namespace blink