d3d11: Privatize d3d11memory implementation Hide most of symbols of GstD3D11Memory object. GstD3D11Memory is one of primary resource for imcoming d3d11 library and it's expected to be a extensible feature. Hiding implementation detail would be helpful for later use case. Summary of this commit: * Now all native Direct3D11 resources are private of GstD3D11Memory. To access native resources, getter methods need to be used or generic map (e.g., gst_memory_map) API should be called apart from some exceptional case such as d3d11decoder case. * Various helper methods are added for GstBuffer related operations and in order to remove duplicated code.
d3d11: Add a helper method for d3d11buffferpool setup Remove duplicated code for d3d11buffferpool setup.
d3d11device: Remove optional helper methods Most of Direct3D11 APIs can be called without GstD3D11Device abstraction. This is a part of prework for public GstD3D11 library to introduce minimal APIs