Implements the cloud console client based on pubsub.

Also makes sure the unittest will succeded when the cloud_console.proto
is not compiled.

BUG=chromium:724523
TEST=unit test.

Change-Id: Ib605c1a2f5dbb2bd871aac272da7f9a4ab7ed35a
Reviewed-on: https://chromium-review.googlesource.com/569453
Commit-Ready: Michael Tang <ntang@chromium.org>
Tested-by: Michael Tang <ntang@chromium.org>
Reviewed-by: Keith Haddow <haddowk@chromium.org>
Reviewed-by: Michael Tang <ntang@chromium.org>
diff --git a/moblab_config.ini b/moblab_config.ini
index 70c04ce..a702404 100644
--- a/moblab_config.ini
+++ b/moblab_config.ini
@@ -37,3 +37,6 @@
 
 # Reduce upload bandwidth for partner by switching on tar and compress results.
 gs_offloader_limit_file_count: True
+
+# Heartbeat rate to the cloud.
+heartbeat_rate_seconds: 0