RendererGLContext supports reparenting a GL context.

content/renderer/pepper_platform_context_3d_impl.cc

Index: content/renderer/pepper_platform_context_3d_impl.cc
===================================================================
--- content/renderer/pepper_platform_context_3d_impl.cc	(revision 89700)
+++ content/renderer/pepper_platform_context_3d_impl.cc	(working copy)
@@ -75,14 +75,16 @@
   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));