Add a new test_list option sync_event_log

With this option disable, events will not get synced to server.

BUG=chrome-os-partner:20854
TEST=run syncshopfloor test, check factory.log has messages like
"Skipped syncing event logs Chunk(log_name='events', len=520, pos=12460)"

Change-Id: If64b03bd5ac091c7fd65fde4b8d5921609c08392
Reviewed-on: https://gerrit.chromium.org/gerrit/62323
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Queue: Cheng-Yi Chiang <cychiang@chromium.org>
Tested-by: Cheng-Yi Chiang <cychiang@chromium.org>
diff --git a/py/goofy/goofy.py b/py/goofy/goofy.py
index 17fab6f..995af52 100755
--- a/py/goofy/goofy.py
+++ b/py/goofy/goofy.py
@@ -1773,6 +1773,11 @@
     Args:
       chunks: A list of Chunk objects.
     '''
+    if not self.test_list.options.sync_event_log:
+      logging.info('Skipped syncing event logs %s',
+          ', '.join([str(chunk) for chunk in chunks]))
+      return
+
     first_exception = None
     exception_count = 0
 
diff --git a/py/test/factory.py b/py/test/factory.py
index e38800c..ece2c56 100644
--- a/py/test/factory.py
+++ b/py/test/factory.py
@@ -384,6 +384,9 @@
   sync_event_log_period_secs = None
   _types['sync_event_log_period_secs'] = (type(None), int)
 
+  # Syncing event logs to server.
+  sync_event_log = True
+
   # Interval to use when checking for factory software updates.
   update_period_secs = None
   _types['update_period_secs'] = (type(None), int)