Generate renewal and expiry events

The android timer class was not generating timer events correctly. This caused
renewal and expiration events not to be sent. A strong pointer to the
timer thread was not held and this caused the android util timer
thread to exit after firing once. This is now addressed.

Bug: 8736545

Merge of https://widevine-internal-review.googlesource.com/#/c/5353/
from the Widevine CDM repository.

Change-Id: I2d904e55d4d10eacc1a51f1c6b5c1a267c92c8d8

libwvdrmengine/cdm/test/Android.mk

@@ -35,5 +35,9 @@ test_name := request_license_test
 test_src_dir := .
 include $(LOCAL_PATH)/unit-test.mk
 
+test_name := timer_unittest
+test_src_dir := ../core/test
+include $(LOCAL_PATH)/unit-test.mk
+
 test_name :=
 test_src_dir :=