Move special DEPTH_STENCIL attachment logic from command buffers to WebGL1

gpu/command_buffer/common/gles2_cmd_utils.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 
 #include <GLES2/gl2.h>
@@ skipping 1423 matching lines @@
 }
 
 uint32_t GLES2Util::GetChannelsNeededForAttachmentType(
     int type,
     uint32_t max_color_attachments) {
   switch (type) {
     case GL_DEPTH_ATTACHMENT:
       return kDepth;
     case GL_STENCIL_ATTACHMENT:
       return kStencil;
-    case GL_DEPTH_STENCIL_ATTACHMENT:
-      return kDepth | kStencil;
     default:
       if (type >= GL_COLOR_ATTACHMENT0 &&
           type < static_cast<int>(
               GL_COLOR_ATTACHMENT0 + max_color_attachments)) {
         return kRGBA;
       }
       return 0x0000;
   }
 }
 
@@ skipping 420 matching lines @@
   }
 
   return true;
 }
 
 #include "gpu/command_buffer/common/gles2_cmd_utils_implementation_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu