Fix the crash issue for debug version when restoring texture binding at Unit 0 in DrawingBuffer::pr…

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 1642 matching lines @@
 void WebGLRenderingContext::deleteShader(WebGLShader* shader)
 {
     deleteObject(shader);
 }
 
 void WebGLRenderingContext::deleteTexture(WebGLTexture* texture)
 {
     if (!deleteObject(texture))
         return;
     for (size_t i = 0; i < m_textureUnits.size(); ++i) {
-        if (texture == m_textureUnits[i].m_texture2DBinding)
+        if (texture == m_textureUnits[i].m_texture2DBinding) {
             m_textureUnits[i].m_texture2DBinding = 0;
+            if (!i)
+                m_drawingBuffer->setTexture2DBinding(0);
+        }
         if (texture == m_textureUnits[i].m_textureCubeMapBinding)
             m_textureUnits[i].m_textureCubeMapBinding = 0;
     }
     if (m_framebufferBinding)
         m_framebufferBinding->removeAttachmentFromBoundFramebuffer(texture);
 }
 
 void WebGLRenderingContext::depthFunc(GC3Denum func)
 {
     if (isContextLost())
@@ skipping 3903 matching lines @@
 
 void WebGLRenderingContext::multisamplingChanged(bool enabled)
 {
     if (m_multisamplingAllowed != enabled) {
         m_multisamplingAllowed = enabled;
         forceLostContext(WebGLRenderingContext::AutoRecoverSyntheticLostContext);
     }
 }
 
 } // namespace WebCore