Fix WebGL context restoration logic. The retry mechanism was broken when the ownership of the WebGr…

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 4212 matching lines @@
 
 blink::WebLayer* WebGLRenderingContextBase::platformLayer() const
 {
     return isContextLost() ? 0 : m_drawingBuffer->platformLayer();
 }
 
 Extensions3DUtil* WebGLRenderingContextBase::extensionsUtil()
 {
     ASSERT(!isContextLost());
     if (!m_extensionsUtil)
-        m_extensionsUtil = adoptPtr(new Extensions3DUtil(webContext()));
+        m_extensionsUtil = Extensions3DUtil::create(webContext());
     return m_extensionsUtil.get();
 }
 
 void WebGLRenderingContextBase::removeSharedObject(WebGLSharedObject* object)
 {
     m_contextGroup->removeObject(object);
 }
 
 void WebGLRenderingContextBase::addSharedObject(WebGLSharedObject* object)
 {
@@ skipping 1193 matching lines @@
 
     if (!frame->loader().client()->allowWebGL(settings && settings->webGLEnabled()))
         return;
 
     // If the context was lost due to RealLostContext, we need to destroy the old DrawingBuffer before creating new DrawingBuffer to ensure resource budget enough.
     m_drawingBuffer.clear();
 
     blink::WebGraphicsContext3D::Attributes attributes = m_requestedAttributes->attributes(canvas()->document().topDocument().url().string(), settings);
     OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes, 0));
     RefPtr<DrawingBuffer> drawingBuffer;
+    // Even if a non-null WebGraphicsContext3D is created, until it's made current, it isn't known whether the context is still lost.
     if (context) {
         RefPtr<WebGLRenderingContextEvictionManager> contextEvictionManager = adoptRef(new WebGLRenderingContextEvictionManager());
 
         // Construct a new drawing buffer with the new WebGraphicsContext3D.
         DrawingBuffer::PreserveDrawingBuffer preserve = m_requestedAttributes->preserveDrawingBuffer() ? DrawingBuffer::Preserve : DrawingBuffer::Discard;
         drawingBuffer = DrawingBuffer::create(context.release(), clampedCanvasSize(), preserve, contextEvictionManager.release());
         // If DrawingBuffer::create() fails to allocate a fbo, |drawingBuffer| is set to null.
     }
     if (!drawingBuffer) {
         if (m_contextLostMode == RealLostContext) {
@@ skipping 203 matching lines @@
         if (m_textureUnits[i].m_texture2DBinding
             || m_textureUnits[i].m_textureCubeMapBinding) {
             m_onePlusMaxNonDefaultTextureUnit = i + 1;
             return;
         }
     }
     m_onePlusMaxNonDefaultTextureUnit = 0;
 }
 
 } // namespace WebCore