Parameterize PeerConnection media tests for Unified Plan

Bug: webrtc:8765
Change-Id: I9bcd053c3e5f6524576f8da9f818de82fcd1836d
Reviewed-on: https://webrtc-review.googlesource.com/41020
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21754}
diff --git a/rtc_base/gunit.cc b/rtc_base/gunit.cc
new file mode 100644
index 0000000..c4631cd
--- /dev/null
+++ b/rtc_base/gunit.cc
@@ -0,0 +1,28 @@
+/*
+ *  Copyright 2018 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.
+ */
+
+#include "rtc_base/gunit.h"
+
+#include <string>
+
+#include "rtc_base/stringutils.h"
+
+::testing::AssertionResult AssertStartsWith(const char* str_expr,
+                                            const char* prefix_expr,
+                                            const std::string& str,
+                                            const std::string& prefix) {
+  if (rtc::starts_with(str.c_str(), prefix.c_str())) {
+    return ::testing::AssertionSuccess();
+  } else {
+    return ::testing::AssertionFailure()
+           << str_expr << "\nwhich is\n\"" << str << "\"\ndoes not start with\n"
+           << prefix_expr << "\nwhich is\n\"" << prefix << "\"";
+  }
+}