Make WebGL extensions get lost when context is lost.

Source/core/html/canvas/WebGLRenderingContext.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 687 matching lines @@
         return p->settings()->privilegedWebGLExtensionsEnabled();
     return false;
 }
 
 void WebGLRenderingContext::addCompressedTextureFormat(GC3Denum format)
 {
     if (!m_compressedTextureFormats.contains(format))
         m_compressedTextureFormats.append(format);
 }
 
+void WebGLRenderingContext::removeAllCompressedTextureFormats()
+{
+    m_compressedTextureFormats.clear();
+}
+
 WebGLRenderingContext::~WebGLRenderingContext()
 {
     // Remove all references to WebGLObjects so if they are the last reference
     // they will be freed before the last context is removed from the context group.
     m_boundArrayBuffer = 0;
     m_defaultVertexArrayObject = 0;
     m_boundVertexArrayObject = 0;
     m_vertexAttrib0Buffer = 0;
     m_currentProgram = 0;
     m_framebufferBinding = 0;
     m_renderbufferBinding = 0;
 
     for (size_t i = 0; i < m_textureUnits.size(); ++i) {
       m_textureUnits[i].m_texture2DBinding = 0;
       m_textureUnits[i].m_textureCubeMapBinding = 0;
     }
 
     m_blackTexture2D = 0;
     m_blackTextureCubeMap = 0;
 
     detachAndRemoveAllObjects();
+
+    // release all extensions
+    for (size_t i = 0; i < m_extensions.size(); ++i)
+        delete m_extensions[i];
+
     destroyGraphicsContext3D();
     m_contextGroup->removeContext(this);
 
     if (m_multisamplingObserverRegistered) {
         Page* page = canvas()->document()->page();
         if (page)
             page->removeMultisamplingChangedObserver(this);
     }
 
     willDestroyContext(this);
@@ skipping 3408 matching lines @@
                 frame->loader()->client()->didLoseWebGLContext(m_context->getExtensions()->getGraphicsResetStatusARB());
         }
     }
 
     // Make absolutely sure we do not refer to an already-deleted texture or framebuffer.
     m_drawingBuffer->setTexture2DBinding(0);
     m_drawingBuffer->setFramebufferBinding(0);
 
     detachAndRemoveAllObjects();
 
+    // Lose all the extensions.
+    for (size_t i = 0; i < m_extensions.size(); ++i) {
+        ExtensionTracker* tracker = m_extensions[i];
+        tracker->loseExtension();
+    }
+
+    removeAllCompressedTextureFormats();
+
     if (mode != RealLostContext)
         destroyGraphicsContext3D();
 
     ConsoleDisplayPreference display = (mode == RealLostContext) ? DisplayInConsole: DontDisplayInConsole;
     synthesizeGLError(GraphicsContext3D::CONTEXT_LOST_WEBGL, "loseContext", "context lost", display);
 
     // Don't allow restoration unless the context lost event has both been
     // dispatched and its default behavior prevented.
     m_restoreAllowed = false;
 
@@ skipping 1296 matching lines @@
 
 void WebGLRenderingContext::multisamplingChanged(bool enabled)
 {
     if (m_multisamplingAllowed != enabled) {
         m_multisamplingAllowed = enabled;
         forceLostContext(WebGLRenderingContext::AutoRecoverSyntheticLostContext);
     }
 }
 
 } // namespace WebCore