AU: Send a previous version event after reboot following an update.
The previous version event is sent along with the first update check. This is
best effort -- if the update check doesn't reach the server, the event is lost.
BUG=9198
TEST=unit tests, tested on device
Change-Id: I5ceb7c8e99ae54eb331f6ac58b8977d2a111461c
Review URL: http://codereview.chromium.org/5993007
diff --git a/prefs.cc b/prefs.cc
index 223fc9b..1bde4cd 100644
--- a/prefs.cc
+++ b/prefs.cc
@@ -19,6 +19,7 @@
const char kPrefsLastActivePingDay[] = "last-active-ping-day";
const char kPrefsLastRollCallPingDay[] = "last-roll-call-ping-day";
const char kPrefsManifestMetadataSize[] = "manifest-metadata-size";
+const char kPrefsPreviousVersion[] = "previous-version";
const char kPrefsResumedUpdateFailures[] = "resumed-update-failures";
const char kPrefsUpdateCheckResponseHash[] = "update-check-response-hash";
const char kPrefsUpdateStateNextDataOffset[] = "update-state-next-data-offset";