Reason for revert: Previous mode aligns with other encoders, and RC_TIMESTAMP_MODE might have issues with no frames for several seconds. Original issue's description: > Use RC_TIMESTAMP_MODE for OpenH264. > > Performs rate control based on timestamp deltas instead of announced > frame rate. > > BUG=webrtc:5855 > R=hbos@webrtc.org > > Committed: https://crrev.com/c4deee49a3ec42b7fe83c82f750539b36aae1d3f > Cr-Commit-Position: refs/heads/master@{#12611} TBR=hbos@webrtc.org # Skipping CQ checks because original CL landed less than 1 days ago. NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true BUG=webrtc:5855 Review-Url: https://codereview.webrtc.org/1950973002 Cr-Commit-Position: refs/heads/master@{#12629}