Split EGL_CHROMIUM_sync_control into EGL_ANGLE_sync_control_rate eglGetMscRateCHROMIUM was added to EGL_CHROMIUM_sync_control based on the original extension GLX_OML_sync_control. However, this new function is not universally implemented. This CL moves it to a new extension, EGL_ANGLE_sync_control_rate, and renames it to eglGetMscRateANGLE. Bug: chromium:1064078 Change-Id: Ia2a29c6776b2b2bf2b98e58ee83b5f141ed01301 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2118154 Commit-Queue: Jonah Ryan-Davis <jonahr@google.com> Reviewed-by: Tim Van Patten <timvp@google.com>