Move SrtpSession and tests to their own files.

webrtc/pc/srtptestutil.h

+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_PC_SRTPTESTUTIL_H_
+#define WEBRTC_PC_SRTPTESTUTIL_H_
+
+#include <string>
+
+namespace rtc {
+
+extern const char CS_AES_CM_128_HMAC_SHA1_32[];
+extern const char CS_AEAD_AES_128_GCM[];
+extern const char CS_AEAD_AES_256_GCM[];
+
+static const uint8_t kTestKey1[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234";
+static const uint8_t kTestKey2[] = "4321ZYXWVUTSRQPONMLKJIHGFEDCBA";
+static const int kTestKeyLen = 30;
+
+static int rtp_auth_tag_len(const std::string& cs) {
+  if (cs == CS_AES_CM_128_HMAC_SHA1_32) {
+    return 4;
+  } else if (cs == CS_AEAD_AES_128_GCM || cs == CS_AEAD_AES_256_GCM) {
+    return 16;
+  } else {
+    return 10;
+  }
+}
+static int rtcp_auth_tag_len(const std::string& cs) {
+  if (cs == CS_AEAD_AES_128_GCM || cs == CS_AEAD_AES_256_GCM) {
+    return 16;
+  } else {
+    return 10;
+  }
+}
+
+}  // namespace rtc
+
+#endif  // WEBRTC_PC_SRTPTESTUTIL_H_