Use visitDOMWrapper to preserve WebGL JS object wrappers

third_party/WebKit/Source/modules/webgl/WebGLObject.h

 /*
  * 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
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebGLObject_h
 #define WebGLObject_h
 
+#include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "wtf/Assertions.h"
 
 namespace gpu {
 namespace gles2 {
 class GLES2Interface;
 }
 }
@@ skipping 34 matching lines @@
     // object()==0 indicates the OpenGL resource is deleted.
     bool isDeleted() { return m_deleted; }
 
     // True if this object belongs to the group or context.
     virtual bool validate(const WebGLContextGroup*, const WebGLRenderingContextBase*) const = 0;
     virtual bool hasObject() const = 0;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 
 protected:
+    // To allow WebGL[2]RenderingContextBase to call visitChildDOMWrappers.
+    friend class WebGLRenderingContextBase;
+    friend class WebGL2RenderingContextBase;
+
     explicit WebGLObject(WebGLRenderingContextBase*);
 
     // deleteObjectImpl should be only called once to delete the OpenGL resource.
     // After calling deleteObjectImpl, hasObject() should return false.
     virtual void deleteObjectImpl(gpu::gles2::GLES2Interface*) = 0;
 
     virtual bool hasGroupOrContext() const = 0;
 
     void detach();
     void detachAndDeleteObject();
 
     virtual gpu::gles2::GLES2Interface* getAGLInterface() const = 0;
 
+    virtual void visitChildDOMWrappers(v8::Isolate*, const v8::Persistent<v8::Object>&) { }
+
 private:
     unsigned m_attachmentCount;
     bool m_deleted;
 };
 
 } // namespace blink
 
 #endif // WebGLObject_h