RendererGLContext supports reparenting a GL context.

gpu/command_buffer/service/gpu_scheduler.h

Index: gpu/command_buffer/service/gpu_scheduler.h
===================================================================
--- gpu/command_buffer/service/gpu_scheduler.h	(revision 89700)
+++ gpu/command_buffer/service/gpu_scheduler.h	(working copy)
@@ -63,13 +63,13 @@
                   const gles2::DisallowedExtensions& disallowed_extensions,
                   const char* allowed_extensions,
                   const std::vector<int32>& attribs,
-                  GpuScheduler* parent,
-                  uint32 parent_texture_id,
                   gfx::GLShareGroup* share_group);
 
   void Destroy();
   void DestroyCommon();
 
+  bool SetParent(GpuScheduler* parent_scheduler, uint32 parent_texture_id);
+
   void PutChanged(bool sync);
 
   // Sets whether commands should be processed by this scheduler. Setting to
@@ -152,9 +152,7 @@
       const gfx::Size& size,
       const gles2::DisallowedExtensions& disallowed_extensions,
       const char* allowed_extensions,
-      const std::vector<int32>& attribs,
-      gles2::GLES2Decoder* parent_decoder,
-      uint32 parent_texture_id);
+      const std::vector<int32>& attribs);
 
 
  private: