RendererGLContext supports reparenting a GL context.

webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc

 // Copyright (c) 2011 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.
 
 #if defined(ENABLE_GPU)
 
 #include "webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h"
 
 #include <GLES2/gl2.h>
 #ifndef GL_GLEXT_PROTOTYPES
@@ skipping 570 matching lines @@
   if (onscreen) {
     if (render_surface == gfx::kNullPluginWindow) {
       LOG(ERROR) << "Invalid surface handle for onscreen context.";
       command_buffer_.reset();
     } else {
       if (!gpu_scheduler_->Initialize(render_surface,
                                       gfx::Size(),
                                       ::gpu::gles2::DisallowedExtensions(),
                                       allowed_extensions,
                                       attribs,
-                                      NULL,
-                                      0,
                                       share_group.get())) {
         LOG(ERROR) << "Could not initialize GpuScheduler.";
         command_buffer_.reset();
       }
     }
   } else {
-    GpuScheduler* parent_scheduler =
-        parent_.get() ? parent_->gpu_scheduler_ : NULL;
-
     if (!gpu_scheduler_->Initialize(render_surface,
                                     size,
                                     ::gpu::gles2::DisallowedExtensions(),
                                     allowed_extensions,
                                     attribs,
-                                    parent_scheduler,
-                                    parent_texture_id_,
                                     share_group.get())) {
       LOG(ERROR) << "Could not initialize offscreen GpuScheduler.";
       command_buffer_.reset();
     }
   }
   if (!command_buffer_.get()) {
     Destroy();
     return false;
   }
 
@@ skipping 1173 matching lines @@
   if (context_lost_callback_) {
     context_lost_callback_->onContextLost();
   }
 }
 
 }  // namespace gpu
 }  // namespace webkit
 
 #endif  // defined(ENABLE_GPU)