Adding instrumentation to locate the source of jankiness.
Mechanical change that adds instrumentation required to locate the source of jankiness (i.e. a long-running fragment of code executed as a part of the task that causes jank) in the code. See the bug for details on what kind of jank we are after.
A number of similar CLs were landed, and none of them caused issues. They've helped to find and fix janky code. The code of the instrumentation is highly optimized and is not expected to affect performance. The code simply creates a diagnostic task which is identical to ones created by PostTask or IPC message handlers.
Landing as TBR since this is a mechanical, safe and temporary change.
This CL instruments code invoked from AccountTracker::OnRefreshTokenAvailable, which is responsible for 20.6 jph.
BUG=422460
TBR=brettw@chromium.org
Review URL: https://codereview.chromium.org/
676123002
Cr-Commit-Position: refs/heads/master@{#301267}