Re-land "WebGL: Transfer ownership of WebGraphicsContext3D to DrawingBuffer"

Source/core/html/canvas/WebGLDrawBuffers.cpp

 /*
  * Copyright (C) 2013 Google 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
@@ skipping 61 matching lines @@
         if (n != 1) {
             m_context->synthesizeGLError(GL_INVALID_VALUE, "drawBuffersWEBGL", "more than one buffer");
             return;
         }
         if (bufs[0] != GL_BACK && bufs[0] != GL_NONE) {
             m_context->synthesizeGLError(GL_INVALID_OPERATION, "drawBuffersWEBGL", "BACK or NONE");
             return;
         }
         // Because the backbuffer is simulated on all current WebKit ports, we need to change BACK to COLOR_ATTACHMENT0.
         GLenum value = (bufs[0] == GL_BACK) ? GL_COLOR_ATTACHMENT0 : GL_NONE;
-        m_context->webGraphicsContext3D()->drawBuffersEXT(1, &value);
+        m_context->webContext()->drawBuffersEXT(1, &value);
         m_context->setBackDrawBuffer(bufs[0]);
     } else {
         if (n > m_context->maxDrawBuffers()) {
             m_context->synthesizeGLError(GL_INVALID_VALUE, "drawBuffersWEBGL", "more than max draw buffers");
             return;
         }
         for (GLsizei i = 0; i < n; ++i) {
             if (bufs[i] != GL_NONE && bufs[i] != static_cast<GLenum>(GL_COLOR_ATTACHMENT0_EXT + i)) {
                 m_context->synthesizeGLError(GL_INVALID_OPERATION, "drawBuffersWEBGL", "COLOR_ATTACHMENTi_EXT or NONE");
                 return;
             }
         }
         m_context->m_framebufferBinding->drawBuffers(buffers);
     }
 }
 
 // static
 bool WebGLDrawBuffers::satisfiesWebGLRequirements(WebGLRenderingContextBase* webglContext)
 {
-    blink::WebGraphicsContext3D* context = webglContext->webGraphicsContext3D();
+    blink::WebGraphicsContext3D* context = webglContext->webContext();
     Extensions3DUtil* extensionsUtil = webglContext->extensionsUtil();
 
     // This is called after we make sure GL_EXT_draw_buffers is supported.
     GLint maxDrawBuffers = 0;
     GLint maxColorAttachments = 0;
     context->getIntegerv(GL_MAX_DRAW_BUFFERS_EXT, &maxDrawBuffers);
     context->getIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &maxColorAttachments);
     if (maxDrawBuffers < 4 || maxColorAttachments < 4)
         return false;
 
@@ skipping 58 matching lines @@
     if (supportsDepth)
         context->deleteTexture(depth);
     if (supportsDepthStencil)
         context->deleteTexture(depthStencil);
     for (size_t i = 0; i < colors.size(); ++i)
         context->deleteTexture(colors[i]);
     return ok;
 }
 
 } // namespace WebCore