Roll src/third_party/cros_system_api/ 9ec6b6802..50b570a8b (6 commits)

https://chromium.googlesource.com/chromiumos/platform2/system_api.git/+log/9ec6b6802d3f..50b570a8b17f

$ git log 9ec6b6802..50b570a8b --date=short --no-merges --format='%ad %ae %s'
2020-11-17 pbond system_api: extend ArcDataSnapshotd d-bus interface
2020-11-06 yichengli u2fd: Add DBus method to check authenticator availability
2020-11-15 cylai system_api: attestation add public key field
2020-10-22 gerow vm_tools: concierge: allow writable rootfs
2020-11-13 ahassani system_api: Unify AU project's owners
2020-09-09 yichengli u2fd: Support canceling WebAuthn operations

Created with:
  roll-dep src/third_party/cros_system_api

Bug: None
Change-Id: I0ca854e58e7480967762adac00b4594c10a75219
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2544786
Commit-Queue: Yicheng Li <yichengli@chromium.org>
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Auto-Submit: Yicheng Li <yichengli@chromium.org>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#828466}

DEPS

@@ -902,7 +902,7 @@ deps = {
 
   # For Linux and Chromium OS.
   'src/third_party/cros_system_api': {
-      'url': Var('chromium_git') + '/chromiumos/platform2/system_api.git' + '@' + '9ec6b6802d3f94a59b72834ea752f3290611190d',
+      'url': Var('chromium_git') + '/chromiumos/platform2/system_api.git' + '@' + '50b570a8b17ffa988d2d670b78b850b2b159d5b4',
       'condition': 'checkout_linux',
   },