Restrict uses of BoringSSL.

(This is a merge of http://go/wvgerrit/71883)

This moves all the SSL code to privacy_crypto so we can use the
iOS-specific versions and not use any BoringSSL.  The iOS version
doesn't support OEM certificates.

Note that the tests still use BoringSSL.

Bug: 126559819
Test: build_and_run_all_unit_tests.sh
Change-Id: Ib0fad5d95b283b6cd6e02d8a08bcf248c5900bc4

libwvdrmengine/cdm/core/include/privacy_crypto.h

@@ -68,6 +68,23 @@ class RsaPublicKey {
   CORE_DISALLOW_COPY_AND_ASSIGN(RsaPublicKey);
 };
 
+
+/**
+ * Extracts an integer value from the extensions in a certificate.
+ * @param cert A PKCS7 encoded X.509 certificate chain.
+ * @param extension_oid The ID of the extension to get.
+ * @param cert_index The zero-based index of the certificate in the chain to
+ *   fetch from.
+ * @param value [OUT] Will contain the extracted value.
+ * @return True on success, false on error.
+ */
+bool ExtractExtensionValueFromCertificate(const std::string& cert,
+                                          const std::string& extension_oid,
+                                          size_t cert_index, uint32_t* value);
+
+std::string Md5Hash(const std::string& data);
+std::string Sha256Hash(const std::string& data);
+
 }  // namespace wvcdm
 
 #endif  // WVCDM_CORE_PRIVACY_CRYPTO_H_