The precise keyword is used in tessellation shaders but introduced in this extension. EXT_gpu_shader5 introduces a handful of features to shaders. This change only implements the `precise` keyword. Bug: angleproject:3569 Change-Id: I2252b79098eb8ba2d2faa040d7eaed7548b7051e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1939851 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>
