Support ATSC license installation

[ Merge of http://go/wvgerrit/163900/ ]

ATSC licenses can be saved by calling
MediaDrm#setPropertyString("storeAtscLicense",<value>)
where <value> is
"<atsc-key-set-ID>:<license-file-data in Base64 format>"

Before storing an ATSC license a session must be opened and the
ATSC mode must be enabled.

Use MediaDrm#setPropertyString("atscMode","enable");

Bug: 176871821
Test: WV Unit/integration/Luci tests
Test: libwvdrmdrmplugin_hal_test
Test: GtsMediaTestCases
Change-Id: Iec2a8b7f87b1122395d06856202278b92316fdfe

libwvdrmengine/cdm/include/wv_content_decryption_module.h

@@ -194,6 +194,10 @@ class WvContentDecryptionModule : public android::RefBase, public TimerHandler {
   virtual CdmResponseType GetSessionUserId(const CdmSessionId& session_id,
                                            uint32_t* user_id);
 
+  virtual CdmResponseType StoreAtscLicense(
+      const CdmIdentifier& identifier, RequestedSecurityLevel security_level,
+      const CdmKeySetId& key_set_id,
+      const std::string& serialized_license_data);
   virtual bool SetDefaultOtaKeyboxFallbackDurationRules();
   virtual bool SetFastOtaKeyboxFallbackDurationRules();