https://uberchromegw.corp.google.com/i/chromium.perf/builders/Linux%20Perf?numbuilds=200

Several pages have this error:
Traceback (most recent call last):
  File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent.py", line 214, in StopAgentTracing
    client.StopChromeTracing()
  File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/devtools_client_backend.py", line 371, in StopChromeTracing
    backend_id=backend.id)
  File "/b/s/w/ir/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/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 237, in EvaluateJavaScript
    return self._EvaluateJavaScript(expression, context_id, timeout)
  File "/b/s/w/ir/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/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 39, in inner
    inspector_backend._ConvertExceptionFromInspectorWebsocket(e)
  File "/b/s/w/ir/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/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 36, in inner
    return func(inspector_backend, *args, **kwargs)
  File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 501, in _EvaluateJavaScript
    return self._runtime.Evaluate(expression, context_id, timeout)
  File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_runtime.py", line 45, in Evaluate
    res = self._inspector_websocket.SyncRequest(request, timeout)
  File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 110, in SyncRequest
    res = self._Receive(timeout)
  File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 149, in _Receive
    data = self._socket.recv()
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py", line 293, in recv
    opcode, data = self.recv_data()
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py", line 310, in recv_data
    opcode, frame = self.recv_data_frame(control_frame)
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py", line 323, in recv_data_frame
    frame = self.recv_frame()
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py", line 357, in recv_frame
    return self.frame_buffer.recv_frame()
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_abnf.py", line 336, in recv_frame
    self.recv_header()
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_abnf.py", line 286, in recv_header
    header = self.recv_strict(2)
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_abnf.py", line 371, in recv_strict
    bytes_ = self.recv(min(16384, shortage))
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_core.py", line 427, in _recv
    return recv(self.sock, bufsize)
  File "/b/s/w/ir/third_party/catapult/telemetry/third_party/websocket-client/websocket/_socket.py", line 83, in recv
    raise WebSocketTimeoutException(message)
TimeoutException: