UserAgent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36 OPR/48.0.2685.35

Steps to reproduce the problem:
Use powerless PC like Intel(R) Celeron(R) CPU G540 @ 2.50GHz 4GB RAM

1. Open online.sbis.ru wait until loaded
2. Open online.sbis.ru in 2d tab and wait until loaded
3. Open online.sbis.ru in 3d tab and wait until loaded
4. Close 1st tab
5. Close second tab
6. Profit. You have 80%+ CPU utilization in closed tab process. Tab from step 5.

Tab from step 5 have no fire unload event as side effect.

What is the expected behavior?

What went wrong?
Tab from step 5 is closed. But in windows task manager i see process with same pid and it utilizate 80%+ CPU.

Tab from step 5 did not fire 'unload' event.

I think what something wrong with closing tab where SharedWorker jumped.

We have SharedSorker with websocket connect and communicate using MessageChannel with page.

I recorded profile and trace 3 times and compress in zip file each try. 
And record normal work of SharedWorker.

In faster PC problem is not reproduced :(

Did this work before? N/A 

Chrome version: 61.0.3163.100  Channel: stable
OS Version: 7
Flash Version: -
 

Deleted: try-1.zip 5.1 MB

try-1.zip 5.1 MB Download

Deleted: try-2.zip 4.2 MB

try-2.zip 4.2 MB Download

Deleted: try-3.zip 3.5 MB

try-3.zip 3.5 MB Download

Deleted: trace_normal-behavior.json.gz 604 KB

trace_normal-behavior.json.gz 604 KB Download