Ref count WvCdmDecryptionModule in cdm_extended_duration_tests

[ Merge of http://go/wvgerrit/79884 ]

WvCdmDecryptionModule needs to be refcounted since it inherits
from RefBase. The test code instantiates it as a member variable.

Bug: 133188706
Test: WV unit/integration tests
Change-Id: I8ae3d92ae148677ea9a8290a6c0553c1a43e3454

libwvdrmengine/cdm/test/request_license_test.cpp

@@ -1623,8 +1623,9 @@ class TestWvCdmEventListener : public WvCdmEventListener {
 
 class DecryptCallbackTester {
  public:
-  DecryptCallbackTester(android::sp<wvcdm::WvContentDecryptionModule> decryptor,
-                        SubSampleInfo* sub_sample_info)
+  DecryptCallbackTester(
+      const android::sp<wvcdm::WvContentDecryptionModule>& decryptor,
+      SubSampleInfo* sub_sample_info)
    : decryptor_(decryptor),
      sub_sample_info_(sub_sample_info) {}