Expose the update engine function GetEolStatus to dbus client

Chrome side will use this method to check the end of life status of
the device and show notifications corresponding to each status.

BUG=chromium:611816
TEST=chrome compile

Change-Id: I237caaaebe60c9ddc72d111a545a612f8d7e676a
Reviewed-on: https://chromium-review.googlesource.com/350874
Commit-Ready: Xiaoyin Hu <xiaoyinh@chromium.org>
Tested-by: Xiaoyin Hu <xiaoyinh@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
diff --git a/dbus/update_engine/dbus-constants.h b/dbus/update_engine/dbus-constants.h
index 93c955c..86c60dd 100644
--- a/dbus/update_engine/dbus-constants.h
+++ b/dbus/update_engine/dbus-constants.h
@@ -23,6 +23,7 @@
 const char kGetChannel[] = "GetChannel";
 const char kAttemptRollback[] = "AttemptRollback";
 const char kCanRollback[] = "CanRollback";
+const char kGetEolStatus[] = "GetEolStatus";
 
 // Signals.
 const char kStatusUpdate[] = "StatusUpdate";
@@ -32,6 +33,13 @@
   kAttemptUpdateFlagNonInteractive = (1 << 0)
 } AttemptUpdateFlags;
 
+// End of Life status used in the GetEolStatus() D-Bus method.
+typedef enum {
+   kSupported = 0,
+   kSecurityOnly = 1,
+   kEol = 2,
+} EndOfLifeStatus;
+
 // Operations contained in StatusUpdate signals.
 const char kUpdateStatusIdle[] = "UPDATE_STATUS_IDLE";
 const char kUpdateStatusCheckingForUpdate[] =