All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=903176

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=0db5f101effb87c4ce778743b004dfb4c3aa5cb5faf565a074896dbd9e5cc25a


Bot(s) for this bug's original alert(s):

Android Nexus6 WebView Perf

rendering.mobile - Benchmark documentation link:
  https://bit.ly/rendering-benchmarks

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/11c48807e40000

📍 Found significant differences after each of 2 commits.
https://pinpoint-dot-chromeperf.appspot.com/job/11c48807e40000

ServiceWorker: Add the new class ServiceWorkerModuleTreeClient to by asamidoi@google.com
https://chromium.googlesource.com/chromium/src/+/0d4913d31a7a1d3fad1657e6c74391fe4299a119
thread_total_all_cpu_time_per_frame: 98.85 → 96.42 (-2.433)

Close the connection with Blink when USB device permission revoked. by donna.wu@intel.com
https://chromium.googlesource.com/chromium/src/+/c702987b204456bcdee69daa35c0e7bd94007ee8
thread_total_all_cpu_time_per_frame: 96.77 → 98.04 (+1.267)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Benchmark documentation link:
  https://bit.ly/rendering-benchmarks

It doesn't seems related to the CL directly. Extra clean-up action added to each frame for USB device permission revocation case but that's what we want to do. So won't fix this.
Reilly@, what's your opinion? 

The bot where this is alerting is for WebView, where the WebUSB API is not enabled so the code added in your patch should not have any effect on performance.

Looking at the graph it seems like this regression occurred at an earlier change and that is being tracked as  issue 901358 .