Correct AES bit size for generic crypto

Merge from Widevine repo of http://go/wvgerrit/42402

This changes the AES key size back to 128 for keys that are not
entitlment keys.

bug: 72904259
test: unit tests
Change-Id: I07cc56050cafb82c65b67c56df3f18d375047eb8

libwvdrmengine/oemcrypto/test/oec_session_util.h

@@ -370,6 +370,9 @@ class Session {
   // The size of the encrypted message.
   size_t message_size() { return message_size_; }
 
+  // If this session has an entitlement license.
+  bool has_entitlement_license() const { return has_entitlement_license_; }
+
  private:
   // Generate mac and enc keys give the master key.
   void DeriveKeys(const uint8_t* master_key,
@@ -399,6 +402,7 @@ class Session {
   vector<uint8_t> encrypted_usage_entry_;
   uint32_t usage_entry_number_;
   string pst_;
+  bool has_entitlement_license_;
 
   // Clear Entitlement key data. This is the backing data for
   // |entitled_key_array_|.