How to see total memory usage per app?

Activity Monitor > View > All Processes, Hierarchically ought to do it, with a bit of scrolling...

If you're not fussed about having a nice GUI and have a python distro installed, you can use psrecord.

• Open Terminal
• Install with pip install psrecord
• Get the Chrome PID (can use activity monitor)

• Run psrecord, with the --include-children flag, providing the PID as an argument

I would recommend specifying some duration (60s in my examples) otherwise psrecord would continue running until Chrome is terminated.

psrecord will record the CPU usage (%) and Memory usage (MB) which you can have it output as either a plot:

psrecord 95639 --plot chrome.png --include-children --duration 60

or a log file:

psrecord 95639 --log chrome.txt --include-children --duration 60

# Elapsed time   CPU (%)     Real (MB)   Virtual (MB)
       0.000        0.000     1672.918    65500.004
       0.078        2.400     1672.922    65500.004
       0.161        3.200     1672.926    65500.004
       0.245        3.400     1672.926    65500.004
       0.329        4.300     1672.930    65500.004
       0.410        3.400     1672.934    65500.004
       0.492        3.900     1672.938    65500.004
       0.580        2.700     1672.941    65500.004
       0.667        3.200     1672.945    65527.895
       0.748        3.100     1672.945    65500.004
       0.830        3.200     1672.949    65500.004
       0.911        3.000     1672.953    65500.004
       0.993        3.200     1672.953    65500.004
       1.074        3.500     1672.957    65500.004