This series of patches adds support for three extensions:
GOOGLE_display_timing. This provides functionality similar to the proposed EXT_present_timing extension by offering feedback about display-related times and control over when presentation should occur. In the context of this series, this patch also provides infrastructure support needed for the present_id and present_wait extensions, along with support that will be useful in implementing EXT_present_timing.
KHR_present_id. This associates a number with each presentation operation. It is used for KHR_present_wait and I hope to use it with EXT_present_timing as well.
KHR_present_wait. This introduces a new function, WaitForPresentKHR, which blocks until the specified presentation has completed.