RendererGLContext supports reparenting a GL context.

content/renderer/gpu/webgraphicscontext3d_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 "content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h"
 
 #include <GLES2/gl2.h>
 #ifndef GL_GLEXT_PROTOTYPES
@@ skipping 86 matching lines @@
       4);
   if (attributes.canRecoverFromContextLoss == false) {
     if (gpu_info.can_lose_context)
       return false;
   }
 
   GURL active_url;
   if (web_view && web_view->mainFrame())
     active_url = GURL(web_view->mainFrame()->url());
 
+  RendererGLContext* parent_context = NULL;
   if (render_directly_to_web_view) {
     RenderView* renderview = RenderView::FromWebView(web_view);
     if (!renderview)
       return false;
 
     web_view_ = web_view;
     context_ = RendererGLContext::CreateViewContext(
         host,
         renderview->compositing_surface(),
         renderview->routing_id(),
         preferred_extensions,
         attribs,
         active_url);
     if (context_) {
       context_->SetSwapBuffersCallback(
           NewCallback(this,
               &WebGraphicsContext3DCommandBufferImpl::OnSwapBuffersComplete));
     }
   } else {
     bool compositing_enabled = !CommandLine::ForCurrentProcess()->HasSwitch(
         switches::kDisableAcceleratedCompositing);
-    RendererGLContext* parent_context = NULL;
     // If GPU compositing is enabled we need to create a GL context that shares
     // resources with the compositor's context.
     if (compositing_enabled) {
       // Asking for the WebGraphicsContext3D on the WebView will force one to
       // be created if it doesn't already exist. When the compositor is created
       // for the view it will use the same context.
       WebKit::WebGraphicsContext3D* view_context =
           web_view->graphicsContext3D();
       if (view_context) {
         WebGraphicsContext3DCommandBufferImpl* context_impl =
             static_cast<WebGraphicsContext3DCommandBufferImpl*>(view_context);
         parent_context = context_impl->context_;
       }
     }
     context_ = RendererGLContext::CreateOffscreenContext(
         host,
-        parent_context,
         gfx::Size(1, 1),
         preferred_extensions,
         attribs,
         active_url);
     web_view_ = NULL;
   }
   if (!context_)
     return false;
 
+  if (!context_->SetParent(parent_context))
+    return false;
+
   gl_ = context_->GetImplementation();
   context_->SetContextLostCallback(
       NewCallback(this,
                   &WebGraphicsContext3DCommandBufferImpl::OnContextLost));
 
   // TODO(gman): Remove this.
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kDisableGLSLTranslator)) {
     context_->DisableShaderTranslation();
   }
@@ skipping 864 matching lines @@
     context_lost_callback_->onContextLost();
   }
 
   RenderView* renderview =
       web_view_ ? RenderView::FromWebView(web_view_) : NULL;
   if (renderview)
     renderview->OnViewContextSwapBuffersAborted();
 }
 
 #endif  // defined(ENABLE_GPU)