Roll src/third_party/cros_system_api/ 4725eead5..9c3e7ed65 (2 commits)

https://chromium.googlesource.com/chromiumos/platform/system_api.git/+log/4725eead5924..9c3e7ed65adc

$ git log 4725eead5..9c3e7ed65 --date=short --no-merges --format='%ad %ae %s'
2018-04-03 timloh Add constants and proto for updating Crostini App Registry
2018-04-02 derat system_api: Add org.chromium.LockScreenService constants.

Created with:
  roll-dep src/third_party/cros_system_api

Bug: 821662
Change-Id: I15e4f707e7b7060a2bc67f8f75d58d3d71b84995
Reviewed-on: https://chromium-review.googlesource.com/994652Reviewed-by: Nicholas Verne <nverne@chromium.org>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547962}

DEPS

@@ -426,7 +426,7 @@ deps = {
 
   # For Linux and Chromium OS.
   'src/third_party/cros_system_api': {
-      'url': Var('chromium_git') + '/chromiumos/platform/system_api.git' + '@' + '4725eead59243c3f1476745b58efac394df53eef',
+      'url': Var('chromium_git') + '/chromiumos/platform/system_api.git' + '@' + '9c3e7ed65adc533bdff4ec098a34c7bf169a99fe',
       'condition': 'checkout_linux',
   },