Currently we assume that the RasterizeCHROMIUM command to the GPU will rasterize the buffer and use any image textures locked for it when the command is executed by the GPU, so its safe to unlock the texture from the renderer immediately after this commands.

But once we start using DDLs, the GPU process will prepare the DDL asynchronously on a worker thread and we'll need to keep the textures locked until the DDL is executed.