Video and logs are present at https://pantheon.corp.google.com/storage/browser/chromiumos-test-logs/bugfiles/cros/851104/?debugUI=CLOUD

can you run bootperf ?
  http://www.chromium.org/chromium-os/how-tos-and-troubleshooting/measuring-boot-time-performance

I am using recovery image.

chronos@localhost / $ bootstat_summary 
    time %cpu       dt  %dt  event
    2460  10%     2460  10%  pre-startup
    3110  20%      650  57%  post-startup
    3120  20%       10  50%  lockbox-cache-exec
    3120  20%        0 100%  lockbox-cache-start
    3220  23%      100  90%  lockbox-cache-end
    3860  33%      640  88%  chrome-exec
    4120  37%      260  93%  chrome-main
    4550  42%      430  87%  shill-start
    5230  45%      680  65%  login-start-signin-screen
    5250  45%       20  88%  login-wait-for-signin-state-initialize
    6850  51%     1600  72%  login-prompt-visible
    6870  51%       20  88%  boot-complete
    7280  54%      410  99%  mini-android-start
    8080  58%      800  98%  network-wifi-association
    8140  59%       60 100%  network-wifi-configuration
    9060  62%      920  95%  network-wifi-ready
    9160  63%      100 100%  network-wifi-online
    9480  64%      320  98%  arc-setup-for-mini-android-end
   64780  28%    55300  22%  login-success
   65250  29%      470  90%  android-start
   65880  29%      630  99%  chrome-first-render
   66180  30%      300  98%  arc-setup-end
chronos@localhost / $ 

so it's all in ARC++ startup ?

i don't know where it's documented, but a bootchart run might be able to show the lagging processes.  check out  crbug.com/682578#c4  for a short list of things to run to get the graph.