a separate method.
This CL will be followed by other CLs that simplify this method and break out the state specific to this computation
into a separate substate.
The changes are bitexact.
BUG=webrtc:5201, webrtc:5298
Review-Url: https://codereview.webrtc.org/1963493003
Cr-Commit-Position: refs/heads/master@{#12712}