Revert "Revert "Clean up interface to ProgramImpl::link."" Should be fixed now with the fix the prior CL. BUG=angleproject:1123 This reverts commit 63069dfc20bc34fe6962dee694953893ee6fc663. Change-Id: Ie1826673820e3a24f9bb3e4ff5c723ac47570041 Reviewed-on: https://chromium-review.googlesource.com/297050 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>