android: Allow custom artifacts to be passed to result_sink.Post().

I'd like to use this lib to upload Chrome OS tests to rdb as well. Some
of the tests have some artifacts that should be attached to their
results.

So this CL lets the caller of result_sink.Post() specify custom
artifacts.

Bug: 1129654
Change-Id: I35bc4009020d724e38adebb4af3cebd12a7b44be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2504579Reviewed-by: benjamin joyce <bjoyce@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821786}

build/android/pylib/base/result_sink.py

@@ -57,7 +57,7 @@ class ResultSinkClient(object):
         'Authorization': 'ResultSink %s' % context['auth_token'],
     }
 
-  def Post(self, test_id, status, test_log):
+  def Post(self, test_id, status, test_log, artifacts=None):
     """Uploads the test result to the ResultSink server.
 
     This assumes that the rdb stream has been called already and that
@@ -67,6 +67,7 @@ class ResultSinkClient(object):
       test_id: A string representing the test's name.
       status: A string representing if the test passed, failed, etc...
       test_log: A string representing the test's output.
+      artifacts: An optional dict of artifacts to attach to the test.
 
     Returns:
       N/A
@@ -91,8 +92,11 @@ class ResultSinkClient(object):
         'summaryHtml': test_log_formatted,
         'testId': test_id,
     }
+    artifacts = artifacts or {}
     if len(test_log) > report_check_size:
-      tr['artifacts'] = {'Test Log': {'contents': base64.b64encode(test_log)}}
+      artifacts.update({'Test Log': {'contents': base64.b64encode(test_log)}})
+    if artifacts:
+      tr['artifacts'] = artifacts
 
     res = requests.post(url=self.url,
                         headers=self.headers,