Since the very first npm install is called while node_modules is empty, we need to ignore it, but we can track
the start timestamp and record the install even once the installation is completed.
This is pretty experimental, but the goal is to track the performance
of our build over time so that we can more easily track perf regressions.
Currently it's integrated only with gulp tasks, but I'd like to expand it
to tracking travis jobs, protractor/benchpress test runs, npm installs, etc.
No PII is being collected. And the data is collected via a Google Analytics
property owned by the Angular team account.
Closes#4672
Igor Minar