Most of the flaky tests in the last ~20 builds on "Mac10.11 Tests" are due BrowserMinidumpTest.

As of 2016-09-26
https://uberchromegw.corp.google.com/i/chromium.mac/builders/Mac10.11%20Tests?numbuilds=200

Sample crash, although there are no symbols for stack trace:

https://uberchromegw.corp.google.com/i/chromium.mac/builders/Mac10.11%20Tests/builds/2525/steps/telemetry_perf_unittests/logs/stdio

 2016-08-25 23:10:42.913 Chromium[7421:67870] NSWindow warning: adding an unknown subview: <FullSizeContentView: 0x7ffb5a572a00>. Break on NSLog to debug.
  2016-08-25 23:10:42.913 Chromium[7421:67870] Call stack:
  (
      "+callStackSymbols disabled for performance reasons"
  )
  Received signal 11 SEGV_MAPERR 000000000000
   [0x00010656b876]
   [0x7fff99c2652a]
   [0x000104a76000]
   [0x00010893b936]
   [0x00010893a82f]
   [0x0001088cffd4]
   [0x00010893bf48]
   [0x0001076279bb]
   [0x00010656bf2b]
   [0x00010658ed5c]
   [0x00010658f09c]
   [0x00010658f443]
   [0x00010659160d]
   [0x0001065850da]
   [0x000106591014]
   [0x7fff9218f881]
   [0x7fff9216efbc]
   [0x7fff9216e4df]
   [0x7fff9216ded8]
   [0x0001065919ef]
   [0x000106591464]
   [0x0001065ac451]
   [0x00010893ea96]
   [0x00010610682a]
   [0x000106105996]
   [0x000104ca994a]
   [0x000104a72d6a]
   [0x000104a72b54]
   [0x000000000013]
  [end of stack trace]