Revert "Load texture storage extension entry points in RendererGL." This reverts commit 5ec636f67cb65438b71ca46375fa45e33eb2e4ba. Change-Id: I68b87279f08e558948216630259349e4db8481d7 Reviewed-on: https://chromium-review.googlesource.com/272785 Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>