UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36

Steps to reproduce the problem:
1. visit www.vsynctester.com
2. press F12, click on Timeline, and capture severals seconds
3. examine where it places frames, relative to when the rAF callback is called.

vs

1. visit www.vsynctester.com
2. open another tab to chrome://tracing/ and record several seconds
3. save trace info and directly examine output
4. compare 'ts' of Scheduler::BeginFrame to the 'ts' the "rafcallback"

What is the expected behavior?
The location of the 'frames' presented in the F12 timeline should match the location of the 'frames' as seen in the trace.

What went wrong?
chrome://tracing/ shows that the frame starts just before the requestAnimationFrame() callback is called -- matching what is seen on the vsynctester.com web site.

The F12 shows that the requestAnimationFrame() callback is called near the very end of a frame.

This is a contradiction -- they both can not be right.

Did this work before? N/A 

Chrome version: 56.0.2924.87  Channel: stable
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version:
 

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	performance.jpg 113 KB View Download

Deleted: trace.txt 67.5 KB

trace.txt 67.5 KB View Download