blink_perf.css failing on chromium.perf/Android Nexus7v2 Perf

Builders failed on: 
- Android Nexus7v2 Perf: 
  https://build.chromium.org/p/chromium.perf/builders/Android%20Nexus7v2%20Perf


I saw this traceback in the test log:

Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/story_runner.py", line 105, in _RunStoryAndProcessErrorIfNeeded
    state.RunStory(results)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/shared_page_state.py", line 316, in RunStory
    self._current_page, self._current_tab, results)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/tools/perf/benchmarks/blink_perf.py", line 311, in ValidateAndMeasurePage
    model, renderer_thread, trace_events_to_measure)
  File "/b/swarming/w/ir/tools/perf/benchmarks/blink_perf.py", line 211, in _ComputeTraceEventsThreadTimeForBlinkPerf
    intersect_wall_time * b.thread_or_wall_duration / b.bounds.bounds)
ZeroDivisionError: float division by zero

dmurph@, it looks like your CL https://chromium-review.googlesource.com/c/598689 might have broken this. Can you take a look?