Created a unified Android test for coverage.

[ Merge of http://go/wvgerrit/143889 ]

New test binary for generating code coverage information.  Run several
reliable, short runnning unit tests.  Actual test failures do not
affect the result of this test.

Bug: 138941105
Bug: 191681397
Test: Android cdm_coverage_test
Change-Id: I6b74d361a8a0e2896e0489acaa64d264158ecaa4

libwvdrmengine/cdm/test/Android.mk

@@ -50,6 +50,9 @@ test_src_dir := ../core/test
 test_main := ../core/test/test_main.cpp
 include $(LOCAL_PATH)/integration-test.mk
 
+# coverage-test.mk will define test name.
+include $(LOCAL_PATH)/coverage-test.mk
+
 test_name := counter_metric_unittest
 test_src_dir := ../metrics/test
 include $(LOCAL_PATH)/unit-test.mk