Fixed regression in WEBGL_draw_buffers support

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp

 /*
  * Copyright (c) 2010, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 654 matching lines @@
 {
     if (!m_depthStencilBuffer)
         m_gl->GenRenderbuffers(1, &m_depthStencilBuffer);
     m_gl->BindRenderbuffer(GL_RENDERBUFFER, m_depthStencilBuffer);
     if (m_antiAliasingMode == MSAAImplicitResolve)
         m_gl->RenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, m_sampleCount, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
     else if (m_antiAliasingMode == MSAAExplicitResolve)
         m_gl->RenderbufferStorageMultisampleCHROMIUM(GL_RENDERBUFFER, m_sampleCount, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
     else
         m_gl->RenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
+    // For ES 2.0 contexts DEPTH_STENCIL is not available natively, so we emulate it
+    // at the command buffer level for WebGL contexts.
     m_gl->FramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_depthStencilBuffer);
     m_gl->BindRenderbuffer(GL_RENDERBUFFER, 0);
 }
 
 
 
 void DrawingBuffer::clearFramebuffers(GLbitfield clearMask)
 {
     // We will clear the multisample FBO, but we also need to clear the non-multisampled buffer.
     if (m_multisampleFBO) {
@@ skipping 316 matching lines @@
 
     if (m_antiAliasingMode == MSAAImplicitResolve)
         m_gl->FramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, target, m_colorBuffer.textureId, 0, m_sampleCount);
     else
         m_gl->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, target, m_colorBuffer.textureId, 0);
 
     m_gl->BindTexture(GL_TEXTURE_2D, m_texture2DBinding);
 }
 
 } // namespace blink