WebGL: Free temporary GPU resources held by inactive or hidden WebGL.

Source/core/html/canvas/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 804 matching lines @@
     webContext()->stencilMaskSeparate(GL_FRONT, m_stencilMask);
     webContext()->depthMask(m_depthMask);
 }
 
 void WebGLRenderingContextBase::markLayerComposited()
 {
     if (!isContextLost())
         m_drawingBuffer->markLayerComposited();
 }
 
+void WebGLRenderingContextBase::setIsHidden(bool hidden)
+{
+    if (!isContextLost())
+        m_drawingBuffer->setIsHidden(hidden);
+}
+
 void WebGLRenderingContextBase::paintRenderingResultsToCanvas()
 {
     if (isContextLost()) {
         canvas()->clearPresentationCopy();
         return;
     }
 
     if (canvas()->document().printing())
         canvas()->clearPresentationCopy();
 
@@ skipping 4832 matching lines @@
         if (m_textureUnits[i].m_texture2DBinding
             || m_textureUnits[i].m_textureCubeMapBinding) {
             m_onePlusMaxNonDefaultTextureUnit = i + 1;
             return;
         }
     }
     m_onePlusMaxNonDefaultTextureUnit = 0;
 }
 
 } // namespace WebCore