When diagnosing performance problems it can be valuable to see what Chrome is doing "under the hood." One way to get a more detailed view into what's going on is to use the about:tracing tool.

Tracing records activity in Chrome's processes (see multi-process architecture for more on what each process is doing). It records C++ or javascript method signatures in a hierarchical view for each thread in each process. This is a lot of information, but sifting through it can help identify performance bottlenecks, slow operations, and events with irregular lengths (leading to e.g. framerate variation).

To instrument Chrome and add your own custom traces, see Instrumenting Chromium or Javascript code to get more detail.