Allow PSSH data to be unspecified on license renewal

Currently the CDM requires the caller to specify init data both on key
generation and renewal requests. With this change the CDM relaxes
this requirement for renewals.

Bug: 8732893

Merge of https://widevine-internal-review.googlesource.com/#/c/5322/
from Widevine CDM repo

Change-Id: Idf4ad2bdb20023da4f30bc369ed87eb811c1c4d9

libwvdrmengine/cdm/core/include/cdm_engine.h

@@ -96,6 +96,11 @@ class CdmEngine : public TimerHandler {
                            WvCdmEventListener* listener);
   bool DetachEventListener(const CdmSessionId& session_id,
                            WvCdmEventListener* listener);
+
+  // Parse a blob of multiple concatenated PSSH atoms to extract the first
+  // widevine pssh
+  static bool ExtractWidevinePssh(const CdmInitData& init_data,
+                                  CdmInitData* output);
  private:
   // private methods
   // Cancel all sessions
@@ -104,11 +109,6 @@ class CdmEngine : public TimerHandler {
   void ComposeJsonRequest(const std::string& message,
                           CdmProvisioningRequest* request);
 
-  // Parse a blob of multiple concatenated PSSH atoms to extract the first
-  // widevine pssh
-  // TODO(gmorgan): This should be done by the user of this class.
-  bool ExtractWidevinePssh(const CdmInitData& init_data,
-                           CdmInitData* output);
   bool ParseJsonResponse(const CdmProvisioningResponse& json_str,
                          const std::string& start_substr,
                          const std::string& end_substr,

libwvdrmengine/cdm/core/include/cdm_session.h

@@ -33,7 +33,7 @@ class CdmSession {
   bool VerifySession(const CdmKeySystem& key_system,
                      const CdmInitData& init_data);
 
-  CdmResponseType GenerateKeyRequest(const CdmInitData& pssh_data,
+  CdmResponseType GenerateKeyRequest(const CdmInitData& init_data,
                                      const CdmLicenseType license_type,
                                      CdmAppParameterMap& app_parameters,
                                      CdmKeyMessage* key_request,