Chrome Version       : 59.0.3071.115
OS Version: 
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04.5 LTS"
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
GOOGLE_CODENAME=trusty
GOOGLE_ID=Goobuntu
GOOGLE_RELEASE="14.04 201708TL3-2"
GOOGLE_ROLE=laptop
GOOGLE_TRACK=stable

What steps will reproduce the problem?
1. Have two users logged on the GUI
2. Suspend
3. Wake up and unlock X for user1
4. Notice how Chrome for user2 is using at least one full CPU
5. Unlock user2, CPU usage goes back to normal levels

This has being going on for a while (weeks, months). Sorry I only now got around to file a bug.

It happens (almost?) all the time. This time (so don't know how representative) I investigated a bit, there were two processes using 1 CPU each. PID 23825 was stuck at
futex(0x7ffd947cf6ec, FUTEX_WAIT_PRIVATE, 1, NULL) = 0

I don't understand enough to explain why it was using 100% CPU while waiting for a futex (another thread busy-waiting?). Thread 23849 instead was calling repeatedly gettid (always getting the same answer).

Command line for 23825 (23849 is gone now...):
23825 tty6     Sl    42:18 /opt/google/chrome/chrome --type=renderer --field-trial-handle=1 --primordial-pipe-token=9876ACD75319B2B66B4031F6448C3BDE --lang=en-GB --enable-crash-reporter=045b0137-2402-4363-92b4-f84e78c46abf, --extension-process --enable-offline-auto-reload --enable-offline-auto-reload-visible-only --blink-settings=disallowFetchForDocWrittenScriptsInMainFrame=false,disallowFetchForDocWrittenScriptsInMainFrameOnSlowConnections=true --enable-pinch --num-raster-threads=2 --enable-main-frame-before-activation --content-image-texture-target=0,0,3553;0,1,3553;0,2,3553;0,3,3553;0,4,3553;0,5,3553;0,6,3553;0,7,3553;0,8,3553;0,9,3553;0,10,3553;0,11,3553;0,12,3553;0,13,3553;0,14,3553;0,15,3553;0,16,3553;1,0,3553;1,1,3553;1,2,3553;1,3,3553;1,4,3553;1,5,3553;1,6,3553;1,7,3553;1,8,3553;1,9,3553;1,10,3553;1,11,3553;1,12,3553;1,13,3553;1,14,3553;1,15,3553;1,16,3553;2,0,3553;2,1,3553;2,2,3553;2,3,3553;2,4,3553;2,5,3553;2,6,3553;2,7,3553;2,8,3553;2,9,3553;2,10,3553;2,11,3553;2,12,3553;2,13,3553;2,14,3553;2,15,3553;2,16,3553;3,0,3553;3,1,3553;3,2,3553;3,3,3553;3,4,3553;3,5,3553;3,6,3553;3,7,3553;3,8,3553;3,9,3553;3,10,3553;3,11,3553;3,12,3553;3,13,3553;3,14,3553;3,15,3553;3,16,3553;4,0,3553;4,1,3553;4,2,3553;4,3,3553;4,4,3553;4,5,3553;4,6,3553;4,7,3553;4,8,3553;4,9,3553;4,10,3553;4,11,3553;4,12,3553;4,13,3553;4,14,3553;4,15,3553;4,16,3553 --disable-accelerated-video-decode --disable-webrtc-hw-vp8-encoding --service-request-channel-token=9876ACD75319B2B66B4031F6448C3BDE --renderer-client-id=7535 --shared-files=v8_natives_data:100,v8_snapshot_data:101

UserAgentString: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36