I was able to reproduce the test timing out locally

Sample failure: https://logs.chromium.org/v/?s=chromium%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8941272788546106624%2F%2B%2Fsteps%2Fservices_unittests_on_Android_device_Nexus_5X%2F0%2Fstdout

  298.909s Main  Received SIGTERM. Stopping test execution.
C  298.913s Main  ********************************************************************************
C  298.913s Main  Detailed Logs
C  298.913s Main  ********************************************************************************
C  298.916s Main  [TIMEOUT] NetworkContextTest.PreconnectLessThanZero:
C  298.916s Main    Suite execution terminated, probably due to swarming timeout.
C  298.916s Main    Your test may not have run.
C  298.916s Main  ********************************************************************************
C  298.916s Main  Summary
C  298.916s Main  ********************************************************************************
C  298.919s Main  [==========] 1756 tests ran.
C  298.919s Main  [  PASSED  ] 1109 tests.
C  298.919s Main  [  FAILED  ] 1 test, listed below:
C  298.919s Main  [  FAILED  ] NetworkContextTest.PreconnectLessThanZero (TIMEOUT)
C  298.919s Main  
C  298.919s Main  1 FAILED TEST
C  298.919s Main  ********************************************************************************