memory.top_10_mobile_stress failing on 13 builders

Relevant stack trace: 

File "/b/s/w/ira3kkbe/third_party/catapult/telemetry/telemetry/internal/story_runner.py", line 94, in _RunStoryAndProcessErrorIfNeeded
state.RunStory(results)
File "/b/s/w/ira3kkbe/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 75, in traced_function
return func(*args, **kwargs)
File "/b/s/w/ira3kkbe/third_party/catapult/telemetry/telemetry/page/shared_page_state.py", line 299, in RunStory
self._current_page.Run(self)
File "/b/s/w/ira3kkbe/third_party/catapult/telemetry/telemetry/page/__init__.py", line 111, in Run
self.RunPageInteractions(action_runner)
File "/b/s/w/ira3kkbe/tools/perf/page_sets/memory_top_10_mobile.py", line 54, in RunPageInteractions
android_browser.Background()
File "/b/s/w/ira3kkbe/third_party/catapult/telemetry/telemetry/internal/browser/browser.py", line 277, in Background
return self._browser_backend.Background()
File "/b/s/w/ira3kkbe/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 75, in traced_function
return func(*args, **kwargs)
File "/b/s/w/ira3kkbe/third_party/catapult/telemetry/telemetry/internal/backends/chrome/desktop_browser_backend.py", line 606, in Background
raise NotImplementedError
NotImplementedError

The NotImplementedError was added in https://github.com/catapult-project/catapult/commit/d489dd8dabbfa788b7eb3c0d0979b165aead0eb1. Unsure exactly why this was triggered recently.

Via a casual glance, I see https://chromium.googlesource.com/chromium/src/+/99a75259cfd52d1390fc0733f9dc18326c819f6f as a potential culprit. It only touches android code though, so I'm not sure why it would affect mostly desktop tests. (Affected builders are only desktop browsers).