[Resource/User Timing] Spec Updates

Per Action Items from last week's teleconference meeting, I have made the following updates to the Resource and User Timing specs:


1.       [Resource Timing] Updated buffer size from 1000 to 150

Per ACTION-25: Analyze data to see what the recommended buffer size should be, I have changed the default buffer size from 1000 to 150. Based on our previous findings, the 90th percentile of resources per page is 145. Keeping future growth in mind, I have changed the default buffer size to 150. A web developer can always increase this buffer size if needed be using the setResourceTimingBufferSize method.



2.       [Resource Timing] Removed fetchEnd and made secureConnectionStart optional

Per last week's meeting discussion, fetchEnd was removed as it was redundant with responseEnd. The processing model was updated to be clear the secureConnectionStart is an optional attribute.



3.       [Resource Timing] Removed getResourceTimingsByType method

Per agreement in last week's meeting, the getResourceTimingsByType method was removed and the type attribute was kept in the timings array.



4.       [Resource and User Timing] Monotonic Clock section was added

Per discussion, the text for monotonic clock has been updated. We have used the term "system clock" for clarity. Zhiheng, please use this same text in the Navigation Timing spec. The text is as so:

The value of the timing attributes must monotonically increase to ensure timing attributes are not skewed by adjustments to the system clock during the navigation. The difference between any two chronologically recorded timing attributes must never be negative. The user agent must record the system clock at the beginning of the navigation and define subsequent timing attributes in terms of a monotonic clock measuring time elapsed from the beginning of the navigation.

Thanks,
Jatinder