Vulkan: Switch SamplerBinding to Use SharedPtr Another step to remove vk::BindingPointer. SharedPtr is used and SamplerBinding is renamed to SharedSamplerPtr. This also removed RefCountedSampler to avoid direct expose of RefCounted<SamplerHelper> which is risky due to ability of change reference count directly. Bug: angleproject:372268711 Change-Id: Ia6f352186a4f75ab9ce3396f298e33f70cd61a1b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6036294 Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>