Rename CancelKeyRequest

(This is a merge of http://go/wvgerrit/10674 from the Widevine CDM
repository.)

Now that the CE CDM has CloseSession to handle closing sessions, we
can rename CancelKeyRequest on the CDM Engine & CDM Session to better
resemble its purpose and the name it is known by on Android.

Change-Id: I68d55b3be733579e5875ab33d8e94a62fe1f651d

libwvdrmengine/cdm/core/include/cdm_engine.h

@@ -56,7 +56,7 @@ class CdmEngine {
   virtual CdmResponseType RestoreKey(const CdmSessionId& session_id,
                                      const CdmKeySetId& key_set_id);
 
-  virtual CdmResponseType CancelKeyRequest(const CdmSessionId& session_id);
+  virtual CdmResponseType RemoveKeys(const CdmSessionId& session_id);
 
   // Construct valid renewal request for the current session keys.
   virtual CdmResponseType GenerateRenewalRequest(const CdmSessionId& session_id,

libwvdrmengine/cdm/core/include/cdm_session.h

@@ -42,9 +42,6 @@ class CdmSession {
   virtual CdmResponseType AddKey(const CdmKeyResponse& key_response,
                                  CdmKeySetId* key_set_id);
 
-  // CancelKeyRequest() - Cancel session.
-  virtual CdmResponseType CancelKeyRequest();
-
   // Query session status
   virtual CdmResponseType QueryStatus(CdmQueryMap* key_info);
 
@@ -100,6 +97,13 @@ class CdmSession {
     is_usage_update_needed_ = false;
   }
 
+  // ReleaseCrypto() - Closes the underlying crypto session but leaves this
+  // object alive. It is invalid to call any method that requires a crypto
+  // session after calling this. Since calling this renders this object mostly
+  // useless, it is preferable to simply delete this object (which will also
+  // release the underlying crypto session) rather than call this method.
+  virtual CdmResponseType ReleaseCrypto();
+
   bool DeleteLicense();
 
  private: