RendererGLContext supports reparenting a GL context.

content/renderer/pepper_platform_context_3d_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.
 
 #include "content/renderer/pepper_platform_context_3d_impl.h"
 
 #include "content/renderer/render_thread.h"
 #include "content/renderer/gpu/renderer_gl_context.h"
 #include "content/renderer/gpu/gpu_channel_host.h"
 #include "content/renderer/gpu/command_buffer_proxy.h"
@@ skipping 57 matching lines @@
     RendererGLContext::DEPTH_SIZE, 24,
     RendererGLContext::STENCIL_SIZE, 8,
     RendererGLContext::SAMPLES, 0,
     RendererGLContext::SAMPLE_BUFFERS, 0,
     RendererGLContext::NONE,
   };
   std::vector<int32> attribs(kAttribs, kAttribs + ARRAYSIZE_UNSAFE(kAttribs));
   CommandBufferProxy* parent_command_buffer =
       parent_context_->GetCommandBufferProxy();
   command_buffer_ = channel_->CreateOffscreenCommandBuffer(
-      parent_command_buffer,
       gfx::Size(1, 1),
       "*",
       attribs,
-      parent_texture_id_,
       GURL::EmptyGURL());
   if (!command_buffer_)
     return false;
+
+  if (!command_buffer_->SetParent(parent_command_buffer, parent_texture_id_))

[piman, 2011/06/22 00:53:27]

Actually this broke pepper. At this point the GpuCommandBufferStub is created
but not yet Initialized (the CommandBufferProxy hasn't been initialized). It
causes a crash in the gpu process in GpuCommandBufferStub::OnSetParent
(scheduler_ is NULL).

[apatrick_chromium, 2011/06/22 17:53:14]

Okay I'll look into it.

+    return false;
+
   command_buffer_->SetChannelErrorCallback(callback_factory_.NewCallback(
       &PlatformContext3DImpl::OnContextLost));
 
   return true;
 }
 
 void PlatformContext3DImpl::SetSwapBuffersCallback(Callback0::Type* callback) {
   DCHECK(command_buffer_);
   command_buffer_->SetSwapBuffersCallback(callback);
 }
@@ skipping 17 matching lines @@
 }
 
 void PlatformContext3DImpl::OnContextLost() {
   DCHECK(command_buffer_);
 
   if (context_lost_callback_.get())
     context_lost_callback_->Run();
 }
 
 #endif  // ENABLE_GPU