Translator: Be more explicit about precisions GLSL ES requires that every symbol (variable, block member, function parameter and return value) is appropriately qualified with a precision, either individually or through the global precision specifier. Some tree transformations however produced symbols with EbpUndefined precision. In text GLSL output, these would produce unqualified symbols which was often incorrect. In this change, the transformations are made to produce explicit / more consistent precisions. The validation (that caught these issues) is not included in this change as there are still a few corner cases left to address. Bug: angleproject:4889 Bug: angleproject:6132 Change-Id: Icca8a0a5476f8646226e7243aa8f501f44acc164 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3075127 Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>