Add decrypt hash support

[ Merge of http://go/wvgerrit/68083 ]

Add ability to query decrypt hash support, set a hash computed over a frame
and retrieve the last error at a later point.

Bug: 34080802
Test: WV unit/integration tests. New tests added to cdm_engine_test,
      libwvdrmdrmplugin_hidl_test and request_license_test.

Change-Id: I7548c8798c873a6af3e1cfc0df57c117e1e474a6

libwvdrmengine/cdm/core/include/cdm_engine.h

@@ -274,6 +274,16 @@ class CdmEngine {
 
   virtual size_t SessionSize() const { return session_map_.Size(); }
 
+  static CdmResponseType ParseDecryptHashString(const std::string& hash_string,
+                                                CdmSessionId* id,
+                                                uint32_t* frame_number,
+                                                std::string* hash);
+  virtual CdmResponseType SetDecryptHash(const CdmSessionId& session_id,
+                                         uint32_t frame_number,
+                                         const std::string& hash);
+  virtual CdmResponseType GetDecryptHashError(const CdmSessionId& session_id,
+                                              std::string* hash_error_string);
+
   // Is the key known to any session?
   virtual bool IsKeyLoaded(const KeyId& key_id);
   virtual bool FindSessionForKey(const KeyId& key_id, CdmSessionId* sessionId);