Address review comments

Merge from Widevine repo of http://go/wvgerrit/96163

This CL just addresses some review comments from the big merge to
master. The header OEMCryptoCENC.h is now synced with the
document http://go/oemcrypto.

Test: unit tests
Bug: 148907684
Change-Id: Ic825126e0dd3d7e86eefab2c51b4abb5d57fb568

libwvdrmengine/oemcrypto/test/oec_session_util.h

@@ -177,7 +177,6 @@ class RoundTrip {
   CoreRequest& core_request() { return core_request_; }
   CoreResponse& core_response() { return core_response_; }
   ResponseData& response_data() { return response_data_; }
-  ResponseData& encrypted_response_data() { return encrypted_response_data_; }
   std::vector<uint8_t>& encrypted_response_buffer() {
     return encrypted_response_;
   }