Chrome on a MacBook Pro laptop running OS X Yosemite (10.10.5) that I was using became unresponsive. Activity Monitor showed a Google Chrome process was using about 100% of the CPU cycles.
I wanted to see what web sites the process was accessing in the browser tabs associated with the process. One way to do so is to double-click on the Chrome process in the Activity Monitor, which will open a smaller window showing information on that process. Click on the Open Files and Ports tab on that window.
Click in the area where the files and ports are listed and hit the command and "A" keys simultaneously to select all of the text in the area. Then hit command-C to copy all of the text into the clipboard. Then paste the text into a text editor using command-V.
You can then use the grep utility to search for all instances of the IP address assigned to the network interface in use on the system you are using. E.g., if the system has an IP address of 192.168.0.9 and I saved the data from the Activity Monitor window to a file named open-sites.txt; I could then use the following command to get a list of the sites that the Chrome process is accessing in the open browser tabs associated with that process. The fully qualified domain name (FQDN) will be shown for those entries that have a PTR DNS record while IP addresses will be shown for those that do not have such records. I could see that many of the websites were hosted on Amazon Web Services (AWS) servers, since the domain name associated with them was amazonaws.com.
$ grep '192.168.0.9' open-sites.txt 192.168.0.9:50037->stackoverflow.com:https 192.168.0.9:49402->vip1.g-anycast1.cachefly.net:http 192.168.0.9:50078->220.127.116.11:http 192.168.0.9:49320->www.nirsoft.net:http 192.168.0.9:50022->ec2-54-225-174-21.compute-1.amazonaws.com:http 192.168.0.9:49322->arstechnica.com:http 192.168.0.9:49354->46-20-237-100.rdns.melbourne.co.uk:http 192.168.0.9:50041->ec2-54-173-130-161.compute-1.amazonaws.com:http 192.168.0.9:49336->server.healthrising.org:http 192.168.0.9:49337->server.healthrising.org:http 192.168.0.9:50079->18.104.22.168:http 192.168.0.9:50077->22.214.171.124:http 192.168.0.9:49338->server.healthrising.org:http 192.168.0.9:49348->3-125-232-198.static.unitasglobal.net:http 192.168.0.9:49349->3-125-232-198.static.unitasglobal.net:http 192.168.0.9:49350->3-125-232-198.static.unitasglobal.net:http 192.168.0.9:49351->3-125-232-198.static.unitasglobal.net:http 192.168.0.9:49768->ec2-54-174-160-96.compute-1.amazonaws.com:http 192.168.0.9:49732->126.96.36.199:http 192.168.0.9:49795->119.bm-nginx-loadbalancer.mgmt.nym2.adnexus.net:http 192.168.0.9:50047->188.8.131.52:http 192.168.0.9:49890->stackoverflow.com:https 192.168.0.9:49389->184.108.40.206:http 192.168.0.9:50075->220.127.116.11:http 192.168.0.9:50226->stackoverflow.com:https 192.168.0.9:50723->ec2-107-22-191-138.compute-1.amazonaws.com:http 192.168.0.9:49538->ec2-54-175-226-189.compute-1.amazonaws.com:http 192.168.0.9:49473->ec2-54-87-217-165.compute-1.amazonaws.com:http 192.168.0.9:49429->ec2-54-87-217-165.compute-1.amazonaws.com:http 192.168.0.9:49431->ec2-54-87-217-165.compute-1.amazonaws.com:http 192.168.0.9:50239->stackoverflow.com:https 192.168.0.9:49728->ec2-54-175-226-189.compute-1.amazonaws.com:http 192.168.0.9:49780->18.104.22.168:http 192.168.0.9:50760->22.214.171.124:http 192.168.0.9:49840->ec2-52-1-103-237.compute-1.amazonaws.com:http 192.168.0.9:49490->ec2-54-87-217-165.compute-1.amazonaws.com:http 192.168.0.9:49514->ec2-54-87-217-165.compute-1.amazonaws.com:http 192.168.0.9:49530->ec2-54-87-217-165.compute-1.amazonaws.com:http 192.168.0.9:49842->ec2-52-1-103-237.compute-1.amazonaws.com:http 192.168.0.9:49934->ce-in-f125.1e100.net:jabber-client 192.168.0.9:49923->glbnylb.about.com:http 192.168.0.9:49750->ec2-54-210-92-58.compute-1.amazonaws.com:http 192.168.0.9:50016->ec2-52-202-9-62.compute-1.amazonaws.com:http 192.168.0.9:49781->126.96.36.199:http 192.168.0.9:49755->188.8.131.52:http 192.168.0.9:49955->184.108.40.206:http 192.168.0.9:49965->220.127.116.11:http 192.168.0.9:49726->18.104.22.168:http 192.168.0.9:49994->sc.iasds01.com:https 192.168.0.9:49997->ec2-52-71-144-157.compute-1.amazonaws.com:https 192.168.0.9:50711->a2.ac.a86c.ip4.static.sl-reverse.com:http $
I killed the Chrome process on the system by clicking on the Apple icon in the upper, left-hand corner of the screen and selecting Force Quit, and then clicking on Chrome to select it and then clicking on the Force Quit button. After I reopened Chrome and chose to restore the session, I no longer had the CPU usage problem. I suspect that some misbehaving script on one of the websites may have caused the problem.